User manual AUDI V6 BITURBO

[. . . ] 198 Service. The 2. 7-litre V6 Biturbo Design and Function Self-study Programme 198 All rights reserved. AUDI AG Dept. I/GS-5 D-85045 Ingolstadt Fax +49. 841/89-6367 740. 2810. 17. 20 Technical status: 01/98 Printed in Germany For internal use only The 2. 7-litre V6 biturbo . . . . . . . Turbocharged engines are already something of a tradition at AUDI. The task now facing AUDI's engineers was to develop a worthy successor to the 5-cylinder turbocharged engine. One of the key development goals for the turbocharged engine was to achieve a good level of dynamic response, particularly at the bottom end of the rev band. [. . . ] Integrated in the accelerator position sender is a "mechanical pressure point " which conveys an authentic "kickdown feel" to the driver. When the driver operates the kickdown, the full-load voltage of the accelerator position sender is exceeded. If a voltage defined in the engine control unit is attained in the process, this is interpreted as a kickdown and transferred to the automatic gearbox (via CAN-Bus). The accelerator position senders for the manual gearboxes and automatic gearboxes are identical. Kickdown is enabled or disabled via the accelerator limit stop (refer to chapter on "TDI engines"). Resistance in SSP 198/25 G79 G185 Lever LL Accelerator travel SSP 198/12 Acc. position sender Accelerator 38 Self-diagnosis/emergency running If a fault occurs in the accelerator position sender or the wiring, two emergency running programs can be run depending on fault type. Emergency running program 1 If an accelerator position sender fails: · · · Accelerator position limited to a defined value. In the case of implausible signals between G79 and G185, the lower value is used. Prerequisite: The idling speed position must be learnt once by the intact sender. The signal supplied by brake light switch for brake pedal switch F47 indicates the idling speed. The fault lamp for electric throttle control K132 comes on. At idling speed, the accelerator position senders G79 and G185 are not diagnosed. If the plug of the accelerator position sender drops off, no fault is stored in the control unit. The engine runs at idling speed and does not respond to the accelerator pedal. · · · Emergency running program 2 If both accelerator position senders fail, driver input recognition is not possible: · · The engine only runs at idling speed. The fault lamp for electric throttle control K132 comes on. Safety function: For safety reasons, the throttle valve is closed as far as a defined angular position when both the accelerator pedal and the brake pedal are depressed. If the brake is pressed first followed by the accelerator pedal, the driver input (torque request) is executed. 39 Subsystems of the Motronic throttle valve control part J338 with throttle valve drive G186, angle senders 1 G187 and 2 G188 for throttle valve drive The throttle valve control part comprises. . . angle senders for throttle valve drive G187 and G188 Activated by the engine control unit, the throttle valve drive controls the air-flow rate necessary to develop the required torque. Feedback on momentary throttle valve position is provided by two potentiometers G187 and G188. If an angle sender fails, the second sender maintains the electronic accelerator function via an emergency running program. Angle senders G187 and G188 cannot be replaced separately. Redundancy means: superfluous, non-essential. Resistance in SSP 198/27 G188 Throttle valve drive G186 (Electric throttle control) Throttle valve housing with throttle valve G187 0 Throttle valve opening in % 100% SSP 198/28 Angle senders for throttle valve drive G187 and G188 40 Housing cover with electrical connections Functional positions of throttle valve control part (linear representation) The engine control unit recognises four key functional positions of the throttle valve control part. · The lower mechanical limit stop Lower mechanical limit stop The throttle valve is closed. This position is required to adapt the angle sender. SSP 198/24 · The lower electrical limit stop Position of lower electrical limit stop is defined by the control unit and is located just below the lower mechanical limit stop. During operation, the throttle valve closes no further than the lower electrical limit stop. This prevents the throttle valve working its way into the throttle valve housing. SSP 198/22 · The emergency running position is the position of the throttle valve in the deenergised state and ensures that air flow is sufficient if any of the relevant electronic accelerator functions fails. Very limited vehicle operation is possible. Emergency running position SSP 198/21 41 Subsystems of the Motronic · The upper electrical limit stop is defined in the control unit does not need to be learned. Position at upper electrical limit stop As in the fully open position, the shaft diameter is greater than the thickness of the throttle butterfly. SSP 198/23 Upper mechanical limit stop To enable the exact angular position of the throttle valve to be identified, angle senders for throttle valve drive G187 and G188 must be learnt . [. . . ] The CCS must be enabled or disabled using the "login procedure" function (as with TDI engines). When the control unit is enabled, a "G" appears in the control unit identification (refer to Workshop Manual). 61 Functional diagram Components: F F36 F47 F96 Brake light switch Clutch pedal switch Brake pedal switch Altitude sender (integrated in engine control unit) Coolant temperature sender Fuel pump Engine speed sender Charge pressure sender Lambda probe (cylinder bank 1) Hall sender (cylinder bank 2) Intake air temperature sender Knock sensor (cylinder bank 1) Coolant temperature sender Knock sensor (cylinder bank 2) Air mass meter Accelerator position sender 1 Lambda probe (cylinder bank 2) Hall sender (cylinder bank 1) Accelerator position sender 2 Throttle valve drive (electric throttle control) Angle sender 1 for throttle valve drive Angle sender 2 for throttle valve drive Sender 1 for exhaust gas temperature Sender 2 for exhaust gas temperature Fuel pump relay Motronic control unit throttle valve control part Warning lamp for electric throttle control Ignition coil, cylinder 1 Injector, cylinder 1 Injector, cylinder 2 Injector, cylinder 3 Injector , cylinder 4 Solenoid valve for charge pressure control Solenoid valve for activated charcoal canister Injector, cylinder 5 Injector, cylinder 6 Output stage (cylinder bank 1) Ignition coil, cylinder 2 Ignition coil, cylinder 3 Ignition coil, cylinder 4 Ignition coil, cylinder 5 N189 N192 N205 N208 N249 Z19 Z28 I II Ignition coil, cylinder 6 Output stage (cylinder bank 2) Camshaft adjustment valve 1 (cylinder bank 1) Camshaft adjustment valve 2 (cylinder bank 2) Divert air valve for turbocharger Heater for lambda probe Heater for lambda probe 2 To dash panel insert To dash panel insert (warning lamp) G2 G6 G28 G31 G39 G40 G42 G 61 G62 G66 G70 G79 G108 G163 G185 G186 G187 G188 G235 G236 J17 J220 J338 K132 Additional signals 1 2 3 4 5 6 7 8 9 10 11 12 CAN-high (automatic gearbox) CAN-low (automatic gearbox) , , Set/decelerate" signal for cruise control system "Off" signal without cancellation for cruise control system "On/Off" signal with cancellation for cruise control system Resume/accelerate" signal for cruise control system Road speed signal Immobiliser/diagnosis signal Air conditioner compressor "On/Off" signal Coolant temperature signal Engine speed signal Fuel consumption signal N N30 N31 N32 N33 N75 N80 N83 N84 N122 N128 N158 N163 N164 62 Colour codes: Input signal Output signal Positive Earth Bidirectional 30 15 31 30 15 31 J17 from ignition lock terminal 15 Note: For the correct fuse rating, please refer to the current flow diagram G235 G236 t° Cruise control op. switch Y N122 N P Q N128 P Q N158 P Q N163 P Q N164 P Q N189 P Q N192 Z t° B N30 N31 N32 N33 N83 N84 N80 N75 N249 N205 N208 B B B B B A A J220 + Z + + + + I _ M G6 G70 ml G39 Z19 t° t° t° G108 Z28 G28 G61 G66 G188 G187 G186 G79 G185 G163 G40 G2 G62 G42 G31 1 Y 2 3 4 5 6 7 8 9 10 11 12 K132 to the brake lights terminal 30a A B II Body earth 31 F36 F47 F Body earth Engine earth 31 SSP 198/18 63 Self-diagnosis Vehicle diagnosis, test and information system VAS 5051 VAS 5051 has the following three operating modes: Vehicle self-diagnosis · · Communication via the vehicle's diagnosis interface Offers the functional capability of currently available diagnosis testers V. A. G 1551 and V. G 1552 Test instruments · Measurement of the vehicle's electrical parameters (voltage, current, resistance) and testing of diodes DMO (Digital Memory Oscilloscope) for representing the voltage curves of the various individual sensors and actuators · Guided fault finding · · Vehicle and control unit identification A test plan is prepared on the basis of the fault messages issued by the the selfdiagnosis, the fault description of customer complaints or assumptions regarding the cause of the trouble. You will find introductory notes and technical information on this system in Self-Study Programme 202. [. . . ]