EOBD … a further step toward protecting and maintaining out atmosphereSP39_02In the USA On-Board Diagnosis is already a fixed element of the range of measures aimed at reducing and monitoring exhaust emissions. This diagnosis system was also introduced in the European Union (EU) at beginning of the year 2000; other European countries have also decided to adopt these rules. The diagnosis system, known as Euro OnBoard Diagnosis (EOBD) has been harmonised to European emission legislation. The first step of this introduction initially covers petrol engines; it will be extended in the foreseeable future to also include diesel engines.The European version of the diagnosis system differs only slightly from the American OBD II system. The EOBD is likewise characterised by the central diagnostic interface and the exhaust warning light. On-Board Diagnosis represents an inestimable contribution aimed at protecting and maintaining our atmosphere. You can acquaint yourself with the fundamentals and the components of the system in this Self Study Programme.Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�2GBContentsIntroduction Detecting Engine Load Lambda Sensors Diagnosis Components Self-Diagnosis Terms Test Your Knowledge 4 8 10 14 29 32 33Servicexxxxxxxxxxxxxxxx FABIAServicexxxxxxxxxxxxxxxx FABIAService Service Service Service Servicexxxxxxxxxxxxxxxx FABIA xxxxxxxxxxxxxxxx FABIA xxxxxxxxxxxxxxxx FABIA xxxxxxxxxxxxxxxx FABIA xxxxxxxxxxxxxxxx FABIAS e r v i c eXXXXXXXXXXXXX XXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXX XXXXXXXXYou will find notes on inspection and maintenance, setting and repair instructions in the Workshop Manual.Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�GB3IntroductionEOBDHistory The first efforts aimed at reducing the emissions which were polluting the atmosphere by setting legal limits, began as early as the seventies. Even in those days, it was clear that such efforts could not be limited only to reducing the pollutants emitted by industry. As traffic density increased, it was also the exhaust gases of motor vehicles which were increasingly the source of atmospheric pollution.SP39_03In order to counter this trend, a diagnosis system for exhaust-relevant components, On-Board Diagnosis I, was developed in the USA and used in motor vehicles. OBD I underwent further development, and its successor version OBD II came into use from 1985. This diagnosis system offered welcome effects in terms of keeping the air clean.Emission limits100 % 80 % 60 % 40 % 20 % 0% 1975 1980 1985 1990 1995 2000NOx HC CODevelopment of pollutant emissions in CaliforniaSP39_05This diagnosis system was also introduced in Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted the European Union from the beginning of unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness ofEOBD, informationinitially in this document. 2000 under the designation for Copyright by ŠKODA AUTO A. S.� petrol engines, with a subsequent extension to include diesel engines. EOBD does not differ significantly from OBD II. There are differences in respect of individual items in the range of diagnosis components which are monitored in the vehicle. EOBD is an adaptation of the OBD II diagnosis system to match the legal provisions of the EU.SP39_044GBBasic concept of the EOBDMalfunctions and faulty components can produce a considerable increase in the level of pollutants which motor vehicles emit. It is not possible to directly measure the concentration of the monitored pollutant components of CO … carbon monoxide HC … hydrocarbons and NOx … oxides of nitrogen at a technically acceptable cost. That is why, it is necessary to use the engine management system to test the exhaustrelevant components. The advantage which this offers is that faults can be determined directly using a diagnosis data reader.SP39_06EOBD Euro-On-Board DiagnoseThe EOBD has to satisfy the following requirements: – Monitoring of all parts which are essential for the quality of the exhaust Diagnostic capability of exhaustrelevant components – Standardised fault codes for all vehicle manufacturers Fault displayed by commercially– –Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted available diagnostic unless authorised by Š KODA AUTO A. S. ŠKODA AUTOtesters A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�–Standardised diagnostic connection (easily reached from the driver's seat)– Display of the operating conditions which existed when a fault occurred – Definitions of when and how an exhaust-relevant fault has to be displayed– Visual warning indication if operating problems occur in exhaust-relevant components – – Protection of the catalytic converter Storage of faults– Standardised names/abbreviations of components, systems and faultsGB5IntroductionLegal basis The EU passed EU Directive 98/69/EC on 13.10.1998. This laid down that EOBD was mandatory for all Member States of the EU. This relates both to the manufacture as well as to the registration of motor vehicles. This is also important for the introduction of vehicles in the EU and in countries which adopt this Directive into their own national law.E O BDDate of introduction Since 01.01.2000 automobile manufacturers have been able to obtain type testing approval for new vehicle models for the EU only if these are equipped with EOBD.SP39_07Transitional period within the EU The transitional period relates to vehicles which have been given type testing approval up to 31.12.1999 and comply with the emission standards of EU II, D3 or D4. Within Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted the EU, the purchaser was permitted to unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.� register such a respect vehicle only up until 31.12.2000 and to operate it to an unlimited extent without EOBD. Subsequent to this date, vehicles fitted with a petrol engine must be equipped with EOBD when first registered. Type testing approval of motor vehicles in the EUNew vehicle models without EOBD Year 2000 New vehicles without EOBD New vehicles without EOBD (with EU II, D3 or D4) New vehicle models with EOBD Year 2001 New vehicles with EOBDSP39_57SP39_08Registration of new vehicles of purchasers6GBEOBD checks the: – – – – – – – – –SP39_55EOBDHC CO NOx–catalytic converter lambda probes combustion system (misfiring) secondary air system exhaust gas recirculation system fuel tank ventilation system fuel distribution system CAN databus influences resulting from automatic gearbox/engine electronic power controlVehicles fitted with EOBD Even prior to the introduction of EOBD, vehicles were already fitted with components which are of relevance for the EOBD. In the same way, faults detected were already stored in the past in the fault memory. NEW with the EOBD: – Exhaust warning light as a visible element for indicating a fault which occurs in the operating conditions of a vehicle – Possibility of assessing the stored faults at the standardised diagnostic interface using any commercially available OBD data reader, e.g. also for vehicle checks when travelling (in preparation)Indication of fault by exhaust warning light If a fault occurs which results in a deterioration in the quality of the exhaust, the fault is stored in the fault memory, and the exhaust warning light comes on and remains on.SP39_10If there is a risk of the catalytic converter being damaged because of ignition misfiring, the fault is likewise stored in the fault memory, but in this case the exhaust warning light If an exhaust-relevant malfunction is detected, this is indicated to the driver by means of exhaust warning light in the dash panel insert. flashes.Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�SP39_11SP39_09GB7Detecting Engine LoadDepending on the engine management system which is used in the particular vehicle, different approaches are sometimes used for determining the characteristic parameters which are of relevance for the EOBD. This in turn results in variations in the EOBD in respect of the range of diagnosis components which are monitored. A variation exists in the way in which operationally-related states (engine load) are determined in the intake manifold (intake manifold pressure or air mass). The intake manifold pressure or the inducted air mass are required for – calculating the ignition timing point – calculating the moment of injection – and for monitoring the fuel tank ventilation and exhaust gas recirculation systems.Engine management systems with ...detection of intake manifold pressuredetection of air massProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability as an equivalent for measuring the airAUTO actually with respect to the correctness of information in this document. Copyright by ŠKODA A. S.� inductedIntake manifold pressure sender G71Air mass meter G70*IgnitionInjectionIgnitionInjectionEOBDSP39_13EOBDSP39_14*On turbo engines, the charge pressure is measured and assessed additionally by the charge pressure sender.GB8Vehicles, engines and engine management systems (selection)Platform A04 FabiaEngineEngine management system Simos Simos Magneti-Marelli Magneti-Marelli MotronicEngine code lettersDetects1.4-ltr./44 kW 1.4-ltr./50 kW 1.4-ltr./16 V/55 kW 1.4-ltr./16 V/74 kW 2.0-ltr./85 kWAZF AQW AUA AUB AZLIntake manifold pressure Intake manifold pressure Intake manifold pressure Intake manifold pressure Air massPlatform A4 OctaviaEngineEngine management system Motronic Simos MotronicEngine code lettersDetects1.4-ltr./55 kW 1.6-ltr./75 kW 1.8-ltr./110 kW turbo engine 1.8-ltr./132 kW turbo engine 2.0-ltr./85 kWAXP AVU AUM, ARXIntake manifold pressure Air mass Air massProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�MotronicAUQAir massMotronicAQY, AZHAir massGB9Lambda SensorsCharacteristic curve and range of applicationsDetermining the lambda value in the exhaust is nowadays one of the most important components for controlling the composition of the exhaust gases. Use is made for this of lambda sensors, which differ in terms of their design and operation: – – two-point sensors and broadband sensorsExample for installation position of the sensors Sensor downstream of Cat Sensor upstream of Cat Pre-catalytic converter* Catalytic converterSP39_15Two-point sensorS The traditional finger sensor (LSH - lambda sensor heated) and the LSF - lambda sensor flat - are also known as jump sensors or also Protected by copyright. Copying privatejump or commercial two-point unless sensors because offor their in purposes, in part or in whole, is not permitted authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect curve to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.� their characteristic by λ = 1.The voltage US output by the sensor is used for determining the lambda value. The sensors merely indicate whether the mixture which is present is rich (λ 1) or lean (λ 1). They are used both as upstream as well as downstream catalytic converter sensors.UVoltage US Rich mixture Lean mixture Range of jumpSP39_16Broadband lambda sensor The LSU - lambda sensor universal is a new generation of lambda sensors. The lambda value is determined by utilising the pump current Ip calculated in the engine control unit (you can find out more on this on the pages which follow). The curve of the pump current is constantly rising. Lambda control is possible between λ = 0.7 and 4 -- broadband. The broadband sensor is used as an upstream catalytic converter sensor.Ip+0–Pump current Ip Rich mixture Lean mixtureSP39_17*Depending on the engine version, the exhaust system is equipped with a pre-catalytic converter, or not.GB10Design and operationare explained by making use of simplified symbolic representation. Two-point sensor The sensor basically consists of a ceramic body coated on both sides (Nernst cell). The coatings act as electrodes, the one layer being in contact with the ambient air and the other with the exhaust gas. The differing level of oxygen concentrations in the ambient air and in the exhaust produces a voltage US between the electrodes. The voltage is analysed by the engine control unit in order to determine the lambda value.Ambient airCeramic body Exhaust450mVJ537SP39_18ElectrodesPump cell Measuring gapBroadband lambda sensor The broadband sensor is a combination of 2 ceramic cells:Exhaust0– –a Nernst cell (refer to two-point sensor) and a pump cellAIpDifferences in the oxygen concentrations at the electrodes of the Nernst cell, as part of the broadband sensor, also produce a voltage in this case. Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted This effect is used in the reverse way in the case of the pump cell. A drop in the oxygen concentration is produced by applying a voltage to the electrodes.unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�450mVUrefSP39_19In line with the polarity, as much oxygen is pumped into or out of the measuring gap so as to maintain a constant 450 mV at the Nernst cell.Ambient air Nernst cellBottom part of sensor element Ip … Pump current Uref … Reference voltage 11GBLambda SensorsCross-section view of sensor element of the broadband sensor (basic illustration) Do not be confused by the basic illustrations of the pump and the electrodes. These elements in the lambda sensor are, in some cases, only a few millimetres or oven only fractions of a millimetre in size.Sensor elementProtected by copyright. Copying for private or commercial purposes, in part or in whole,Exhaust is not permitted Pump cell with electrodes unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�ElectrodeIpCeramic body ElectrodeUslpJ537Uref1234567J537SP39_59Legend 1 2 3 4 5 6 7 Failure of sensor upstream of Cat (broadband sensor) If no sensor signal is received, the lambda closed-loop control is not active and the lambda adaptation is disabled. The fuel tank ventilation system goes into emergency mode. The secondary air and Cat diagnosis are disabled. The engine control unit makes use of a map control as an emergency function. Pump cell Sensor heater Ambient air passage* Measuring gap Bottom part of sensor element Nernst cell with electrodes Protective layerUS Lambda sensor voltage Pump current Ip Uref Reference voltage* The ambient air is fed in through the sensor cable.Note: The broadband sensor must only be replaced complete with cable and connector because sensor element, cable and connector are matched to each other.12GBControl example (broadband sensor)Richer fuel/air mixture is produced If the fuel/air mixture becomes richer, this means that the oxygen concentration in the exhaust gas and thus also at the electrode at the exhaust side drops. A consequence of this is an increase in the voltage between the electrodes of the Nernst cell. This change is passed as a signal to the engine control unit for analysis. The oxygen concentration at the exhaust electrode must be increased to match in order to again restore the voltage between the electrodes to 450 mV (lambda = 1).Electrodes0AIp450mVUrefJ537Nernst cell Pump cellSP39_24To achieve this, the pump cell now pumps oxygen into the measuring gap. The pump current which is then obtained is an equivalent for the oxygen concentration/ demand and thus a measure for the air index lambda in the exhaust gas. The pump current is analysed in the engine control unit and the necessary leaner mixture is produced.0AIp450mVUrefJ537SP39_25Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted Measuring gap unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.� is producedLeaner fuel/air mixtureIf the fuel/air mixture becomes leaner, the system operates in the same way, except the direction of pumping is reversed. Oxygen is pumped from the measuring gap to the outside.Note: The pumping effect of the pump cell is a purely physical process. When a voltage is applied to the pump cell, oxygen is transported (pumped) through the oxygen-permeable ceramic in line with the polarity. The pump cell is presented in a purely symbolical way in the illustrations.GB13Diagnosis ComponentsOverview of the interlinking of components of the Euro On-Board Diagnosis System05 02 03 04Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�0708 11 09 1501 17 101819 2014EPCGBSystem components (taking the example of the 1.4-ltr. - 16 V 55/74 kW engine) Legend 01 Engine control unit J537 02 Activated charcoal filter 03 Activated charcoal filter solenoid valve N80 04 Injectors cylinder 1 … 4 N30 … N33 05 EGR valve N18 06 Camshaft position sensor G163 07 Throttle valve control unit J338 08 Intake manifold pressure sender G71 and intake manifold temperature sender G72 09 Electronic power control/accelerator Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted pedal position sender G79 and G185 unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability 10 Fuel filter with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.� 11 Knock sensor G61 12 Rotorless high-voltage distribution 13 Lambda sensor (upstream sensor) G39 14 Lambda sensor (downstream sensor) G130 15 Engine speed sender G28 16 Coolant temperature sender G62 14 17 CAN databus 18 Diagnostic interface 19 Exhaust warning light K83 20 Electronic power control fault light K13206121316Note: Other engines/engine management systems may have additional exhaustrelevant system components in comparison to this example, or fewer such components.SP39_26GB15Diagnosis ComponentsComprehensive components monitoringWithin this diagnosis complex all the exhaustrelevant components (sensors and actuators) are monitored in terms of their function. The procedure adopted in this connection complies with defined test criteria.Test criteria – Testing the input and output signals (plausibility) Short circuit to earth Short circuit to positive Open circuit in the wiring– – –Catalytic converterCatalyst conversion diagnosis The engine control unit compares the sensor voltages of the upstream and downstream sensors and forms a ratio which is the basis for evaluating the catalytic converter efficiency. If this ratio differs from the specified range, the engine management system detects a malfunction of the catalytic converter and the fault code is set in the fault memory. In addition, this malfunction is indicated by the exhaust warning light.Catalytic converter o.k.Catalytic converter not o.k.1 U U1 U Ut 2 3tt 2 3tSP39_27SP39_28U = Voltage1 Engine control unitt = by Time Sensor Protected copyright. Copying for private or commercial purposes, in part or in whole, 2 is not permitted upstream of catalytic converter unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liabilitydownstream of catalytic converter 3 Sensor with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.� 16GBVoltage curve shift and adaptation of the upstream sensor Ageing or intoxication of a lambda sensor can result in a displacement of the voltage curves of the upstream sensor (sensor shift). This shift is detected by the engine control unit and compensated for (adapted) within certain limits.Adaptation of upstream sensor o.k.Adaptation of upstream sensor not o.k.1 U U U1 Ut 2 3t 2t 3tSP39_29SP39_30U = Voltage t = Time1 Engine control unit 2 Sensor upstream of catalytic converter 3 Sensor downstream of catalytic converterLambda sensorsNote: The presence of condensation, particularly during the cold-start Diagnosis of the lambda sensor heater phase, can in certain circumstances damage the heated sensor. This risk The engine control unit detects whether the does not exist in the case of the heating capacity of the lambda sensor is in upstream sensor because it is proper order by means of the measurement of Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted positioned very unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept anyclose liability to the engine. the sensor heater resistance. with respect to the correctness of information in this document. Copyright by be ŠKODA AUTO A. up S.� immediately It can heated after the engine is started. At the downstream sensor, though, condensation may occur because of the greater distance to the engine, particularly in the initial phase after the engine is started. That is why this sensor is not heated until a temperature of about 300 ˚C has been reached.GB17Diagnosis ComponentsDiagnosis of reaction time of upstream sensor The reaction time of the upstream sensor can also be detrimentally affected by ageing or intoxication. The fuel/air mixture modulation by the engine control unit is a requirement for diagnosing the reaction time. This modulation is a slight variation between a lean and a rich mixture. It is produced artificially by the engine control unit because the lambda value would be controlled so accurately with the broadband sensor that it would always be exactly lambda = 1. In order to operate properly, however, the catalytic converter requires slight variations in the composition of the mixture. That is why the composition is modulated by the engine control unit.lean mixture Mixture modulationUrich mixtureλ=1U = Voltage t = TimetSP39_31Note: The engine control unit converts the sensor pump current as an actual sensor output signal into a voltage and controls the mixture modulation by means of the sensor voltage.Protected by copyright. Copying for private or commercial sensor purposes, insignal part or in whole, is not permittedable The upstream sensor signal follows the The upstream is no longer unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability modulation of the fuel/air mixture of the to follow the modulation of the fuel/air with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.� engine control unit. mixture of the engine control unit.Upstream sensor o.k.Upstream sensor not o.k.1 U U U1 Ut 2 3t 2t 3tU = Voltage t = TimeSP39_321 Engine control unit 2 Sensor upstream of catalytic converter 3 Sensor downstream of catalytic converterSP39_3318GBDiagnosis of control limit of downstream sensor If the composition of the fuel/air mixture is optimal, the downstream sensor voltage moves within a range which corresponds approximately to lambda = 1. A higher or lower sensor voltage indicates a richer or a leaner mixture. If variations are detected, the engine control unit continues to correct the composition of the fuel/air mixture by means of the lambda control value "m" until the lambda value is again approximately 1. If the control limits which are defined for the lambda value are exceeded, the EOBD detects this as a fault. The causes of such faults may be not only a faulty downstream sensor but also, for example, ageing of the upstream sensor, inadequate efficiency of the catalytic converter or also "unmetered air".Correct control As the oxygen concentration in the exhaust gas rises (lean mixture), the voltage at the downstream sensor drops. The engine control unit thereupon alters the composition of the mixture by means of the lambda control value "m". A richer mixture is produced. The voltage of the downstream sensor rises and the engine control unit is again able to lower the lambda control value.Downstream control loop o.k.1 mb aUt 2 3tSP39_34Control limit exceededIn this case also the oxygen concentration in the exhaust rises (lean mixture) and the sensor voltage also drops initially. 1 The process for producing a richer mixture is initiated but the sensor voltage now continues m U to remain low despite this because of the fault Protected by copyright. Copying for private or commercial purposes, in part b or in whole, is not permitted unless authorised by to ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability which exists. The sensor does not react the with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.� control. aDownstream control loop not o.k.tm= U= t = b = a = Lambda control value Voltage Time Upper control limit Lower control limitt 31 Engine control unit 2 Upstream sensor 3 Downstream sensor2SP39_35GB19Diagnosis ComponentsDiagnosis of movement of downstream sensor Proper operation of the downstream sensor is additionally monitored by the engine control unit checking the signals of the sensor in the deceleration and acceleration modes. The basis for this evaluation is the opening angle of the throttle valve. During acceleration, the oxygen concentration in the exhaust drops, the fuel/air mixture becomes richer and the sensor voltage must rise. In the deceleration mode, the ratios are exactly the opposite. The fuel feed is shut off, which causes the oxygen concentration in the exhaust to rise and the sensor voltage must drop. If these reactions do not occur, the engine control unit detects a faulty downstream sensor.Example for the case of "acceleration of vehicle"Downstream sensor o.k.Downstream sensor not o.k.1 α U α1 Ut 2 3t 2t 3tProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability SP39_36 SP39_37 with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�α = Opening angle of throttle valve U = Voltage t = Time1 Engine control unit 2 Sensor upstream of catalytic converter 3 Sensor downstream of catalytic converter20GBTank ventilation systemFlow diagnosis If a large quantity of fuel is bonded in the activated charcoal filter, the fuel/air mixture is made richer by admixing this fuel bonded in the activated charcoal filter, to the intake air. In the opposite case, it becomes leaner. This change is registered by the upstream sensor and serves as a confirmation for proper operation of the tank ventilation system. Modulation diagnosis The test is conducted with its own test interval. In this case, the solenoid valve for the activated charcoal filter system is opened slightly and closed again in a defined rhythm. This in turn modulates the intake manifold pressure which is detected by the intake manifold pressure sensor, transmitted to the engine control unit where it is analysed.Tank ventilation o.k.Tank ventilation not o.k.1 a P a1 Pt 4 3 2Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�ttt54 3 2SP39_385SP39_39a = Opening stroke of solenoid valve t = Time P = Pressure1 2 3 4 5Engine control unit Tank Activated charcoal filter Solenoid valve for activated charcoal filter system Intake manifold pressure sensor 21GBDiagnosis ComponentsCylinder-selective detection of ignition misfiringIrregular engine running method The engine speed sensors detects irregularities in the engine speed which are caused by ignition misfiring. In combination with the signal supplied by camshaft position sensor, the engine control unit is able to select the cylinder which is the cause of the problem, store the fault and switch on the exhaust warning light.The two methods differ in terms of the analysis of the engine speed signal.Momentary analysis method The momentary analysis method is used, as is the irregular engine running method, to detect ignition misfiring at a particular cylinder on the basis of the signal supplied by the engine speed sensor and the camshaft position sensor. The momentary analysis method compares the irregular engine speed "n", which is the result of the ignition misfiring, with defined computed inputs in the engine control unit.Compression in cylinder 1 (illustration simplified to show only cylinder 1)ntDuring the compression stroke the kinetic energy of the engine is utilised to compress the fuel/air mixture. The speed of the engine decreases.SP39_40n = Engine speed t = TimeBasis for this calculation: – –The momentary variations of the engine which are calculated in this way, are more the torque dependent on engine load meaningful than the results of the irregular Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted and speed engine method. unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A.running S. does not guarantee or accept any liability respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.� the flywheel mass with and the resulting characteristic of the engine speed It is necessary, however, to analyse the characteristic of the engine speed for each engine type and to store this in the engine control unit.22GBCompression is followed by ignition. Engine speed increases. Consequently, engine speed varies each time combustion or compression takes place. If we look at all the cylinders, the result which we obtain is the curve based on the superimposition of the individual engine speed variations. This is transmitted by the engine speed sensor to the engine control unit where it is compared with the computations stored.Ignition in cylinder 1 (illustration simplified to show only cylinder 1)ntSP39_41Detecting ignition misfiring on the basis of the engine speed signaln = Engine speed t = Timeno misfiringMisfiring1 n n1tt22SP39_43SP39_42 n = Engine speed by ŠKODA AUTO A. S. ŠKODA AUTO A. 1 Engine control unit unless authorised S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.� t = Time 2 Engine speed sensorProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permittedIf ignition misfiring occurs, the exhaust warning light comes on and remains on and a fault is stored in the fault memory. If, however, the catalytic converter may be damaged by ignition misfiring, and the curve remains within the dangerous load-engine speed range, the exhaust warning light flashes. The fuel feed to the corresponding cylinder is shut off.GB23Diagnosis ComponentsExhaust gas recirculationPressure diagnosis At the moment the exhaust gas is directed into the intake manifold, the intake manifold pressure sensor detects a rising pressure (i.e. a reduced vacuum). The engine control unit compares this change in pressure with the quantity of the exhaust gases supplied, and deduces from this the function of the exhaust gas recirculation system.EGR o.k.1 P+ t P23Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�SP39_44The diagnosis is carried out only in the deceleration mode (because fuel injection would act as a disturbance variable for the measurement).EGR not o.k.1 P+ t P-P+ = Pressure P– = Vacuum t = Time21 Engine control unit 2 EGR valve 3 Intake manifold pressure sensor3SP39_4524GBSecondary air systemThe upstream sensor signal (broadband sensor) is used for checking the operation of the secondary air system. The broadband sensor supplies detailed results of measurements for evaluation to the engine control unit. The actual secondary air supplied is calculated from the difference (lambda value prior to and during secondary air delivery), and the operation of the secondary air system is checked in this way. This is known as flow diagnosis.Secondary air system o.k.1 2 4 3 5 6 7SP39_46λtSecondary air system not o.k.1λ = Lambda t = Time2 4 3λ1 2 3 4 5 6Engine control unit Secondary air pump relay Secondary air injection valve Secondary air pump Combination valve Sensor upstream of catalytic converter 7 Sensor downstream of catalytic converter5 6 7tSP39_47GBProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�25Diagnosis ComponentsCharge pressure controlCharge pressure limit diagnosisThe charge pressure of turbo engines is checked as part of the EOBD to determine whether it exceeds the maximum permitted charge pressure.This is intended to protect the engine, which will be subjected to excessive loads if the charge pressures are too high.Charge pressure limit is exceeded The maximum permissible charge pressure may be exceeded if a fault exists in the charge pressure control: The charge pressure sensor signals the charge pressure which exists at that moment to the engine control unit, and the engine control unit detects the fault.Guard function is activated Signalling and storing the fault is not sufficient in such a case. It is also necessary to switch off the turbocharger in order to avoid the engine suffering any damage. The "wastegate" of the turbocharger is opened for this purpose and the exhaust gases are diverted around the turbocharger.Charge pressure control not o.k.Guard function is activated1 P+1 P+ 2 2 Pt 5 5 3Exhaust ExhaustP-t34SP39_484SP39_49P = Pressure t = Time1 Engine control unit 2 Charge pressure control solenoid valve 3 Turbocharger with charge pressure control valve 4 Wastegate 5 Charge pressure sensor; in charge air coolerProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability GBA. S.� with respect to the correctness of information in this document. Copyright by ŠKODA AUTO26Electronic Power ControlThe driver request and the signals which are produced as a result, are transmitted by the accelerator pedal module to the engine control unit. The engine control unit uses this information to calculate how the torque request can best be implemented. The request is implemented by operating the throttle valve the position of which is varied by an electric motor, by controlling the ignition and the fuel injection. This enables the position of the throttle valve to be adapted to the particular general conditions which exist in each driving situation.1 2 3 4 5 66321EPC54SP39_56The EOBD also makes use of the diagnosis functions of the Electronic Power Control. Faults are indicated by the electronic power control fault light.Engine control unit Accelerator pedal module Throttle valve control unit Ignition, fuel injection EPC (Electronic Power Control) fault light Additional signals come, for example, from the – cruise control system – air conditioning system – idle speed control – lambda control – automatic gearbox and ABS/ESPProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�If these faults continue to exist in the subsequent driving cycles, the EOBD also switches on the exhaust warning light.The following are tested – – accelerator pedal position sensor angle sensor for throttle valve driveGB27Diagnosis ComponentsCAN databusData diagnosis Each engine control unit is aware of the control units which are exchanging information over the CAN databus. If the "minimum" number of messages is not received, a fault is detected.Control units which make use of the CAN databus, are for example– – – –engine control unit control unit in dash panel insert ABS/ESP control unit automatic gearbox control unitCAN databus operating properly All the control units connected to the particular databus regularly transmit messages to the engine control unit. The latter detects that there is no message missing and that the data transfer is operating properly.Interruption in CAN databus A control unit is not able to transmit information to the engine control unit. The engine control unit registers that information has not been received, identifies the component and stores the fault.CAN databus o.k.CAN databus not o.k.1122Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�ABCABCSP39_51SP39_501 Engine control unit 2 CAN databusA, B, CVarious control units in the vehicle28GBSelf-DiagnosisReadiness codeAs part of the EOBD all exhaust-relevant electrical components are continuously checked to ensure they are operating properly. In addition, diagnoses are conducted of exhaust-relevant systems at regular intervals when driving in order to be able to detect any variations (e.g. in the exhaust gas recirculation system). The readiness code is used as verification for ensuring that the diagnoses have been conducted correctly and completely. The readiness code is an 8-digit numerical code. It does not provide any information of which faults are present in the system. It provides information regarding the status of the diagnosis: 0 - diagnosis has been successfully completed 1 - diagnosis was aborted - was not yet carried out - could not yet be carried out - was not successfully endedMeaning of the 8-digit numerical block for readiness codeProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�Only if all display places are "0" have all the diagnoses been successfully completed. 1 2 3 4 5 6 7 8 0 0 0 Diagnosis function * Catalytic converter Catalytic converter heater Activated charcoal filter system (tank ventilation system) Secondary air system Air conditioning Lambda sensors Lambda sensor heater Exhaust gas recirculation system0 0 0 0 0*Depending on the engine version, it is possible that certain diagnosis functions do not apply. In this case, the readiness code is then always set to "0". You can find more information regarding this in the relevant Workshop Manual.GB29Self-DiagnosisVersion 1 ... with any desired data reader (irrespective of the manufacturer) ... (not yet available at present.Version 2 ... with the V.A.G diagnosis testers 1552, 1551 or with the VAS diagnosis system 5051.… readingreadiness code… generatingVersion 1 conduct a NEDC (New European Driving Cycle)Version 2Version 3 conduct engine-specific test routines with the aid of the V.A.G diagnosis testers or the VAS diagnosis system stateddrive for an adequately long period in average driving mode until all the components of relevance for diagnosis Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. doesdetected not guarantee or accept any liability arewith respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�SP39_5230GBDiagnosis testers The readiness code can be generated and read using the – – – vehicle system tester V.A.G 1552 fault reader V.A.G 1551, and the vehicle diagnosis, measuring and information system VAS 5051Reading readiness code – – – Connect diagnosis tester Switch ignition on Operating mode "Vehicle self-diagnosis"SP33_73Address word 01 … Engine electronics Functions 01 - Interrogating control unit version 02 - Interrogating fault memory 03 - Final control diagnosis 04 - Basic setting 05 - Erasing fault memory 06 - Ending output 07 - Coding control unit 08 - Reading measured value block 15 - Readiness code The readiness code is displayed by selecting address word 01, function 15 or function 08, and display group number 100.SP39_58Note: If the fault memory of the engine control unit is erased, the readiness code is also reset, or erased.Generating readiness code The readiness code can be generated by means of the test routines described in the particular Workshop Manual. The procedure may differ depending on the engine management system. Note: You can find a detailed description of the requirements and the procedure for generating the readiness code in the respective Workshop Manual.Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�GB31TermsAdaptation adapting to changed conditions Lambda control value The lambda control value is determined by the engine control unit on the basis of the signals supplied by the lambda sensors and the operating state of the engine (e.g. engine speed, load). This value is used as a basis for altering the fuel/air mixture until the ratio is optimal for the particular operating state.D2, D3, D4 different emission standards in the Federal Republic of GermanyNEDC New European Driving Cycle for determining the exhaust emissions of motor vehiclesModulation Altering or adapting the modulation frequency of a signalkm/h 120OBD On-Board Diagnosis60Readiness code 8-digit numerical code which indicates the status of the exhaust-relevant diagnoses0 195 390 585 780 1180 sSP39_54SAE code fault code which is defined by the Society of Automotive Engineers, and which is mandatory for all OBD systemsEOBD Euro On-Board DiagnosisProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODAWastegate AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information inas this document. Copyright by ŠKODA AUTO A. S.� (also known bypass)EU II, EU III, EU IV emission standards of the European UnionThe wastegate allows excess exhaust gases to flow past the drive of the turbocharger. This makes it possible to switch the turbocharger off or also to reduce its capacity. LSF Lambda Sensor Flat (two-point sensor) LSH Lambda Sensor Heated (finger sensor) LSU Lambda Sensor Universal (broadband sensor)Lambda (air index, λ) coefficient which describes the air concentration in the fuel/air mixture. λ 1.0 rich mixture λ 1.0 lean mixture λ = 1.0 theoretical optimum mixing ratio of fuel/air Air quantity supplied = Lambda Air demand32GBTest Your KnowledgeWhich answers are correct? Sometimes only one. But, possibly also more than one – or all of them! Please complete the missing points.1.The EOBD A. B. C. is an adaptation of OBD II to match the provisions of the European Union. is identical in all respects to OBD II. applies to all internal combustion engines.2.The broadband sensor A. B. C. has a jump characteristic around λ = 1. is a combination of 2 cells, a Nernst cell and a pump cell. makes it possible to achieve a lambda control between λ = 0.7 and λ = 4.3.Until which date did purchasers of new cars not fitted with EOBD receive an initial registration within the EU provided the new cars complied with the emission standard EU II? A. B. C. 31.12.1999 01.02.2000 31.12.20004.When does the exhaust warning light K83 flash? A. B. C. If the catalytic converter may be damaged by ignition misfiring. Every time a fault occurs in the exhaust system. If an exhaust-relevant fault is stored in the fault memory.Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�GB33Test Your Knowledge5.What are the important points to note when replacing a broadband sensor, A. B. C. that broadband sensor and engine control unit are a system and must therefore be replaced complete. that the broadband sensor must always be replaced complete with cable and connector. that broadband sensor and engine control unit are a system and must therefore be matched to each other.6.The readiness code A. B. provides information of which faults are present in the system. is an 8-digit numerical code which states whether certain diagnoses have been successfully completed, have been aborted, or not yet carried out, could not yet be carried out or were not completed successfully. is an 8-digit numerical code which indicates the status of exhaust-relevant diagnoses.C.7.In order to generate the readiness code A. B. C. carry out an NEDC. warm up the engine to its operating temperature of 60 ˚C and increase engine speed to 2000 rpm. drive a car for an adequately long period in the average driving mode until all the components of relevance for the diagnosis are detected.341. A.; 2. B., C.; 3. C.; 4. A.; 5. B., C.; 6. B., C.; 7. A., C. Answers:GBProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�NotesProtected by copyright. Copying for private or commercial purposes, in part or in whole, is not permitted unless authorised by ŠKODA AUTO A. S. ŠKODA AUTO A. S. does not guarantee or accept any liability with respect to the correctness of information in this document. Copyright by ŠKODA AUTO A. S.�GB35