Audi Workshop Service and Repair Manuals

Special tools and workshop equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598/31
• ◆ VAS 5051 with VAS 5051/1

• or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

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.

Test sequence

• ‒ 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 (12...97 %).

If the display values do not appear as described:

• ‒ Check whether connector of accelerator pedal position has become detached, is not properly engaged or if the contacts of the connector are corroded.
• ‒ Test voltage supply and wiring to accelerator position senders
  .

Testing voltage supply

• ‒ Remove storage compartment on driver's side.

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

• ‒ Unplug connector for accelerator position sender.
• ‒ Switch ignition on.

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

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 24-8.

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

• ‒ Rectify any open/short circuit as necessary.

If no fault is detected in the wiring:

• ‒ Renew accelerator position senders.

=> Fuel supply system, Petrol engines; Repair group 20; Servicing accelerator mechanism - Vehicles with electronic throttle system