Angle Sensors For Throttle Drive -G187- and -G188-, Checking

Angle Sensor For Throttle Valve Actuator, Checking







Special tools and equipment

- VAG 1526 A
- VAG 1594 A
- VAG 1598/31
- VAS 5051 with VAS 5051/1

The Angle sensor -1- for throttle drive (power accelerator actuation) -G187- and Angle sensor -2- for throttle drive (power accelerator actuation) -G188- signal the position of the throttle valve to the engine control module. Both angle sensors are located in the throttle valve control module.

Test sequence

- Connect testing and information system VAS 5051 and select vehicle system "01 - Engine electronics" in selection. Ignition must be switched on. Connecting VAS 5051 Scan Tool

Display on VAS 5051:







- Under -1- select diagnostic function "08 - Read measured value block".

Display on VAS 5051:







1 - Enter display group.
- Enter "062" for "display group number 062" in zone -2- and confirm entry by pressing -Q- button.

Display on VAS 5051:







- Check specified values for electronic throttle potentiometer voltages in display zones -1- and -2-.

Display Group 062:

- Observe readouts in display zones 1 and 2.
- Slowly depress accelerator pedal.

- Percentage displayed in zone 1 should rise evenly. Tolerance range from 3 to 93% is not fully utilized.
- Percentage displayed in zone 2 should fall evenly. Tolerance range from 97 to 3% is not fully utilized.

NOTE:
- The reason why the value in display zone 1 rises and that in zone 2 falls is that the potentiometers (angle sensors) in the throttle valve control module operate in opposite directions.
- This means that the voltage picked off by one of the angle sensors runs in the direction of 5 V. (As the throttle is opened, the voltage becomes greater and the percentage increases).
- The voltage picked off by the angle sensor 2 runs from 5 V in the direction of 0 V. (As the throttle is opened, the voltage becomes smaller and the percentage decreases).

- Exit function "08 - Read measured value block" by pressing <- button.

If the displays are not as described:
- Check throttle valve control module voltage supply and wiring. Pay particular attention to connectors, which may be disconnected or corroded.
- Check accelerator position sensor. Testing and Inspection

Checking The Voltage Supply To The Throttle Valve Control Module.
- Disconnect connector from throttle valve control module.
- Switch ignition on.

- Connect multimeter as follows to measure voltage:







Connector Specified value
terminal

2 + ground approx. 5 V
2 + 6 approx. 5 V

If the specified values are not obtained:

Checking wiring

- Disconnect connector from throttle valve control module.
- Connect test box VAG 1598/31 to wiring harness for engine control module; do not connect engine control module. Wiring and Component Testing Using VAG1598/31 Test Box
- Check for open circuit and short to Ground/positive or Ground in following wiring connections:

Connector Test box VAG 1598/31
terminal Socket

1 92
2 83
3 117
4 84
5 118
6 91

- Repair any open/short circuit as necessary.

If no wiring malfunction is detected:
- Replace throttle valve control module.