Testing and adjusting throttle valve potentiometer — AUDI

The throttle valve potentiometer -G69 is located at the rear of the throttle valve body.

Check function

Connect fault reader V.A.G 1551 (V.A.G 1552) and select control unit for engine electronics => Page
01-2
.
Read measured value block (function 08) and select display group 04 =>Page
01-90
.

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

Observe display in display zone 1.

Specification: 5...10o (accelerator in idling position)

Fully depress accelerator pedal.

Specification: 80...98o

If the specified results are not achieved, check the setting of the throttle cable

=> 8-cylinder engine, Mechanical components; Repair Group 20; Servicing throttle control; Adjusting throttle cable
8-cylinder engine, Mechanical components
Servicing throttle control
Adjusting throttle cable

If the setting of the throttle cable is OK, test idling switch and adjust as necessary => Page
24-63
.

Note:

Adjusting the idling switch also automatically adjusts the throttle valve potentiometer.

If the setting of the idling switch is OK, test the voltage supply for the throttle valve potentiometer.

Testing voltage supply

Pull connector off throttle valve potentiometer.
Switch ignition on.
Connect handheld multimeter V.A.G 1526 for voltage measurement in turn between contacts 1 and 3 and 2 and 3.

Specification: 4.5...5.5 V in each case.

If the specifications are achieved, test the resistance of the throttle valve potentiometer
=>Page
24-85

If one of the specifications is not met, test the wiring to the engine control unit as follows:
Switch off ignition.
Connect test box V.A.G 1598/19 to wiring harness for engine control unit =>Page
24-14
.
Unplug the connector from the throttle valve potentiometer.

Note:

Only use gold-plated contacts when repairing the contacts in the throttle valve positioner connector.

Test the following wires for open circuit and short circuit:

=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations binder

Connector on wiring harness, contact · Test box V.A.G 1598/19 or engine control unit
1 · A3
2 · A19
3 · A24

If the wiring is OK, replace the engine control unit => Page
24-15
.

Testing resistance of throttle valve potentiometer

Unplug the connector from the throttle valve potentiometer.
Measure resistance between contacts 1 and 2 using V.A.G 1526.

Specification: 1.5...2.6 kω

Measure resistance between contacts 2 and 3 using V.A.G 1526.

Specification: 0.75...1.3 kω

Slowly operate throttle valve lever until it is in the end position (full throttle position).

Specification: 2.4...3.6 kω

If one of the values is not as specified, replace the throttle valve potentiometer.

Adjusting throttle valve potentiometer

Adjusting the idling switch also automatically adjusts the throttle valve potentiometer.

Adjusting idling switch =>Page
24-63