Accelerator Pedal Position Sensor: Testing and Inspection

Accelerator Pedal Position Sensor, Checking


Special tools and equipment







- VAG 1526 or Fluke 83 multimeter
- VAG 1594 A Adapter set
- VAG 1598/31 Test box
- VAG 1551 Scan Tool or vehicle system tester VAG 1552 with cable VAG 1551/3
- Wiring diagram

Function
Both sensors for accelerator pedal position -G79- and -G185- are located on the accelerator pedal and communicate the driver's intention to the Engine Control Module (ECM) independently of one another. Both sensors are located in one housing.

Checking sequence
- Connect VAG 1551 (VAG 1552) and with ignition switched on select engine electronics control module with "Address word" 01:

Indicated on display


Rapid data transfer HELP
Select function XX


- Press -0- and -8- buttons to select "Read measured value block" and confirm entry with -Q- button.

Indicated on display


Read Measuring Value Block HELP
Input display group number XXX


- Press -0-, -6- and -2- buttons to select "Display group number 62" and confirm entry with -Q- button.

Indicated on display: (1 to 4 = Display fields)


Read Measuring Value Block 62 ->
1 2 3 4


- Check specifications of sensor 1 (-G79-) at idling stop in display field 3.
- Specification: 12 to 97 %

- Check specifications of sensor 2 (-G185-) at idling stop in display field 4.
- Specification: 4 to 49 %


NOTE: The ECM calculates the voltage values of the angle sensor in percent relative to 5 Volts and displays these as a percentage figure (5 Volt supply voltage equates to 100%).


- Operate accelerator pedal slowly until Wide Open Throttle and observe angle indication in display fields 3 and 4:
- The percent figures in display field 3 must rise evenly. The tolerance range of 12 to 97 % is not covered completely.
- The percent figures in display field 4 must rise evenly. The tolerance range of 4 to 49 % is not covered completely.


NOTE: The figure displayed in display field 3 must always be approximately double that displayed in display field 4.


If the display does not indicate as described:
- Check accelerator pedal position sensor voltage supply and wiring connections.

Checking voltage supply and wiring to control module
- Remove driver's side stowage compartment:
- Disconnect 6-pin connector for accelerator pedal position sensor.
- Switch ignition on.







- Connect multimeter to measure voltage at following contacts of connector:

Contact 1 + Ground
Contact 1 + 5
Contact 2 + Ground
Contact 2 + 3

- Specification: minimum 4.5 V

- Switch ignition off.

If the specifications are not obtained:







- Connect test box VAG 1598/31 to control module wiring harness (The ECM remains disconnected).







- Check wiring between test box and connector for open circuit according to wiring diagram.

Contact 1 + socket 72
Contact 2+ socket 73
Contact 3+ socket 36
Contact 4+ socket 35
Contact 5+ socket 33
Contact 6+ socket 34

- Wire resistance: max. 1.5 Ohms
- Check wiring for short to battery positive or Ground.
- Check wires for short to one another.

If no wiring malfunction is detected:
- Replace accelerator pedal position sensor