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. [. . . ] 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. If a full load is predefined, the power output is increased slowly. 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 fault lamp for electric throttle control K132 does not come on. 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. . . throttle valve housing with throttle valve . . . throttle valve drive G186 with reduction gear . . . 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. For safety reasons, two angle senders (redundancy) are used. They have opposite impedance characteristics (see diagram). 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. The throttle valve control part may not be opened. 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. [. . . ] 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. For self-diagnosis, please use the Workshop Manual in which the procedure for the various individual functions is described. SSP 198/39 VAS 5051 64 Test box V. A. G 1598/31 The new test box V. A. G 1598/31 is used to carry out tests on the Motronic ME 7. 1. It also allows tests to be performed while the engine is running. [. . . ]