Audi Workshop Service and Repair Manuals

→ Fitting location of accelerator position sender -G79 and accelerator position sender 2 -G185

The accelerator pedal position senders -G79 and -G185 are located on accelerator pedal. Both senders inform the engine control unit of the driver's throttle requirement (pedal position) but function completely independently of each other (redundancy principle). Both 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.

• ‒ Enter "08" to select the function "Read measured value block" and confirm entry with Q key.

• ‒ Enter "062" for Display Group 062 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 supply 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 twice as high as 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
  .
• ‒ Adjust accelerator position senders (right-hand drive vehicles only).

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

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.

Left-hand drive vehicles

• ‒ Switch ignition on.

• ‒ → Connect multimeter (voltage measurement range) as follows:

Right-hand drive vehicles

• ‒ Switch ignition on.

• ‒ → Connect multimeter (voltage measurement range) as follows:

All models

If the specifications are obtained:

• ‒ Test the signal wires.

If the specifications are not obtained:

• ‒ Test wiring between engine control unit and accelerator position senders.

Testing wiring

• ‒ 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 24-21.

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 wiring fault is detected:

• ‒ Renew accelerator position senders.

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