Throttle Drive Angle Sensors, Checking

Throttle Drive Angle Sensors, Checking

Special tools, testers and auxiliary items required

• Multimeter (V.A.G 1526 A)

• Connector test kit (V.A.G 1594 A)

• Test box (VAG1598/31)

• Vehicle diagnostic, testing and information system ( VAS 5051)

• adapter (VAS 5051/1)

Angle sensor 1 for throttle drive (power accelerator actuation) (G187) and Angle sensor 2 for throttle drive (power accelerator actuation) (G188) inform the Engine Control Module (ECM) about the position of the throttle valve. Both angle sensors are located in the throttle valve control module.

Work sequence

- Connect vehicle diagnostic, testing and information system (VAS 5051) and select vehicle system "01 -Engine electronics" in selection. Refer to => [ VAS5051, Connecting and Selecting Functions ] VAS 5051, Connecting and Selecting Functions. Ignition must be switched on.

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 field - 2 - and confirm entry by pressing Q button.

Display on (VAS 5051):





- Check specifications for electronic throttle potentiometer voltages in display fields - 1 - and - 2 -.





• The ECM converts and displays the voltage readings from the angle sensors as percentages of 5 V. (A 5 Volt supply corresponds to 100%).

- Observe readouts in display fields 1 and 2.

- Slowly depress accelerator pedal.

Percentage displayed in field 1 should rise evenly. Tolerance range from 3..0.93% is not fully utilized.

Percentage displayed in field 2 should fall evenly. Tolerance range from 97..0.3% is not fully utilized.

• The reason why the value indicated in display field 1 climbs, while the value indicated in display field 2 decreases, has to do with the fact that the potentiometers (angle sensors) in the Throttle Valve Control Module (J338) run in opposite directions.

• This means that the voltage of angle sensor 1 runs from 0 to 5 volts. (The more the throttle valve is opened, the larger the voltage; percent indication climbs).

• The voltage of angle sensor 2 runs from 5 to 0 volts. (The more the throttle valve is opened, the lower the voltage; the percentage decreases).

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

If the displays are not as described:

- Check Throttle Valve Control Module (J338) voltage supply and wiring. Pay particular attention to connectors, which may be disconnected or corroded.

- Check Sender - 2 - for accelerator pedal position (G185) => [ Throttle Position Sensor 1 and Accelerator Pedal Position Sensor 2, Checking ] Throttle Position Sensor 1 and Accelerator Pedal Position Sensor 2, Checking.

Checking voltage supply to Throttle Valve Control Module (J338).

- Disconnect connector from Throttle Valve Control Module (J338).

- Switch ignition on.

- Connect multimeter as follows to measure voltage:









If specified values are not obtained:

Checking wiring connections

- Disconnect connector from Throttle Valve Control Module (J338).





- Connect test box (VAG1598/31) to wiring harness for Engine Control Module (ECM); do not connect Engine Control Module (ECM) => [ Electrical Testing, with Test Box VAG 1598/31 ] Electrical Testing, With Test Box VAG 1598/31.

- Check for open circuit, short to Ground (GND), or short to positive (B+) in following wiring connections:





- Repair any open/short circuit as necessary.

If no malfunctions are found in wires:

- Replace Throttle Valve Control Module (J338).