Accelerator Pedal Position Sensor, Checking

Special tools and equipment







- V.A.G 1526 Hand multimeter
- Scan tool V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
- V.A.G 1594 A Adapter set
- V.A.G 1598/22 Test box
- Current flow diagram

Function
Both sensors for accelerator pedal position -G79- and -G185- are located at the accelerator pedal and communicated the driver's intentions to the Engine Control Module (ECM) fully independently of each other. Both sensors are located in one housing.

Test sequence
- Connect scan tool V.A.G 1551 (V.A.G 1552) and with ignition switched on select engine electronics control unit with the "Address word" 01.

Indicated on display


Rapid data transfer HELP
Select function XX


- Press keys 0 and 8 for the function "Read Measured Value Block" and confirm entry with Q key.

Indicated on display


Read measuring value block HELP
Input display group number XXX


- Press keys 0, 6 and 2 for the "Display group number 62" and confirm entry with Q key.

Indicated on display: (1 - 4 = Display zones)


Basic setting 60 ->
1 2 3 4


- Check throttle valve positioner at idling stop (minimum value) in display zone 2.
- Specification: 65 - 90 %; throttle valve angle in display zone 1 specification: 80 - 95 %
- Check throttle valve positioner at idling stop (minimum value) in display zone 2.
- Specification: 65 - 90 % and throttle valve angle in display zone 1 specification: 80 - 95 %


NOTES: The Engine Control Module (ECM) calculates the voltage value of the angle sensor in percent relative to 5 volts and displays this value (5 volts supply voltage represents 100 %).


- Operate accelerator pedal slowly until Wide Open Throttle and observe the angle indication in display fields 1 and 2:
- The percent indication in display field 1 must rise evenly. Specified range of 3 - 93 % will not be used in it's entirety.


NOTES: The indicated value in display field 3 must always be approximately twice as large as the value in display field 4.


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

Checking voltage supply and wiring to control unit
- Remove driver side storage compartment.
- Disconnect 6 - pin connector for accelerator pedal position sensor.
- Switch ignition on.







- Connect multimeter for voltage measurement at the following terminals of the connector.
- Contact 1 + Ground (GND)
- Terminal 1 + 5
- Terminal 2 + Ground (GND)
- Terminal 2 + 3
- Specified value at least 4.5 V
- Switch ignition off.

If the specifications are not obtained:







- Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit is not connected by this action.







- Check wiring between test box and connector for open circuit according to current flow diagram.
- Contact 1 + socket 24
- Contact 2 + socket 11
- Contact 3 + socket 23
- Contact 4 + socket 12
- Contact 6 + socket 25

Vehicles with automatic gearbox:
- Contact 5 + socket 8
- Wire resistance: max. 1.5 ohms
- Additionally check the wiring for short to battery positive or Ground.
- Additionally check wires for short to one another.

If no wiring malfunction is detected:
- Replace accelerator pedal position sensor, see "Fuel Supply System Components, Removing And Installing" item 4. Service and Repair