Audi Workshop Service and Repair Manuals

Accelerator position senders -G79 and -G185 are located on the accelerator pedal. Both senders inform the engine control unit of the driver's throttle requirement (pedal position), but each functions completely independently of the other (redundancy principle). Both senders are located in a single housing.

• ‒ Connect vehicle diagnostic, testing and information system VAS 5051 (or fault reader V.A.G 1551) and select engine electronics control unit by entering address word "01" ( .)
  When doing this the ignition must be switched on.

• ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

• ‒ Press the keys 0, 6 and 2 to select Display Group 62 and confirm entry with Q key.

• ‒ Check display values for electronic throttle potentiometer voltages.

Note:

The engine control unit converts the voltage readings from the angle senders into percentages of 5 V and displays them as percentages. (A signal voltage of 5 V is equivalent to 100%.)

• ‒ Observe display zones 3 and 4.
• ‒ Slowly depress accelerator to full throttle position.

The percentage value in display zone 3 should rise steadily between 12 and 97 % but without covering the full range of values.

The percentage value in display zone 4 should also rise steadily but without covering the full range of values (in this case 4...49 %).

Note:

The value shown in display zone 3 should always be about double the value shown in display zone 4.

If the display values do not appear as described:

• ‒ Test voltage supply and wiring to accelerator position senders
  .

Testing voltage supply to accelerator position senders

• ‒ Remove storage compartment on driver's side.

=> General body repairs, Interior; Repair group 68; Storage compartments, covers and trim parts; Removing and installing driver's storage compartment

• ‒ Unplug connector for accelerator position sender.

Note:

The connector is clipped onto the pedal bracket near the brake light switch.

Left-hand drive vehicles:

• ‒ Switch ignition on.
• ‒ → Connect hand-held multimeter (voltage range) between the following sockets on the connector:

Right-hand drive vehicles

• ‒ Switch ignition on.

• ‒ → Connect hand-held multimeter (voltage range) between the following sockets on the connector:

All models

If the specifications are obtained:

• ‒ Test the signal wiring => Page 24-168.

If the specifications are not obtained:

• ‒ Test wiring between engine control unit and accelerator position senders => Page 24-168.

Testing signal wiring and wiring connections between accelerator position senders and engine control unit

• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit. Do not connect to the engine control unit itself.
  => Page 24-10.

Left-hand drive vehicles

• ‒ → Test for open circuit and short to positive or earth in the following wiring connections:

Right-hand drive vehicles

• ‒ → Test for open circuit and short to positive or earth in the following wiring connections:

All models

• ‒ Rectify any open/short circuit as necessary.

If no fault is detected:

• ‒ Renew accelerator position senders.

=> Fuel supply system, Petrol engines; Repair group 20; Servicing accelerator linkage - right-hand drive vehicles