Testing accelerator position senders -G79 and -G185: Audi 1.8 (APT, AQE, ARG, ARH, …)

ARG AVV
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" ( => Page
01-3
.)
When doing this the ignition must be switched on.

Rapid data transfer
HELP
Select function XX
Indicated on display:

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

Read measured value block
Q
Enter display group number
XXX
Indicated on display:

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

Read measured value block 62
⇒
1
2
3
4
Indicated on display:

Check display values for electronic throttle potentiometer voltages.

Display zones
1 · 2 · 3 · 4
Display Group 62: Electronic throttle potentiometer voltages with ignition on
Display · xx % · xx % · xx % · xx %
Indicates · Throttle valve angle / (angle sender 1) · Throttle valve angle / (angle sender 2) · Accelerator position / sender · Accelerator position / sender 2
Range · min.: 0 % / max.: 100 % · min.: 0 % / max.: 100 % · min.: 0 % / max.: 100 % · min.: 0 % / max.: 100 %
Specification · 3...93 % · 97...3 % · 12...97 % · 4...49 %

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
=>Page
24-155
.

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
General body repairs, Interior
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:

6-pin connector on / wiring harness, socket · Specification
1 + earth · approx. 5 V
1 + 5 · approx. 5 V
2 + earth · approx. 5 V
2 + 3 · approx. 5 V

Right-hand drive vehicles

Switch ignition on.

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

6-pin connector on / wiring harness, sockets · Specification
2 + earth · approx. 5 V
2 + 3 · approx. 5 V
5 + earth · approx. 5 V
5 + 4 · approx. 5 V

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:

Connector / Socket · Test box V.A.G 1598/31 / Socket
1 · 72
2 · 73
3 · 36
4 (signal wiring) · 35
5 · 33
6 (signal wiring) · 34

Right-hand drive vehicles

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

Connector / Socket · Test box V.A.G 1598/31 / Socket
1 (signal wiring) · 35
2 · 73
3 · 36
4 · 33
5 · 72
6 (signal wiring) · 34

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
Fuel supply system, Petrol engines
Servicing accelerator linkage - right-hand drive vehicles