Throttle Position Sensor: Testing and Inspection

CHECKING THROTTLE POSITION SENSOR

Throttle Position Potentiometer:

NOTE:
- Vehicles with automatic transmissions have two sensors combined in one housing on the throttle body with two wires leading out of the sensor housing.

- The 4-pin connector wiring goes to the (J217) Transmission Control Module (TCM).

- Check the Automatic Transmission sensor by reading the Diagnostic Trouble Code (DTC) Memory.

- The 3-pin connector wiring goes to the (J169) Digifant Engine Control Module (ECM) (this connector is also used in Automatic transmission vehicles).

- After removing, installing or replacing the Throttle Position (TP) sensor, check the idle speed.

The Digifant ECM obtains the following information from the TP sensor:

- With throttle in closed position:

^ Switches OFF fuel supply during deceleration fuel shut off.
^ Idle speed control.
^ Ignition timing at idle.

- With throttle partially opened:

^ Injection quantity for acceleration enrichment.

- With throttle completely open:

^ Injection quantity for full throttle enrichment.





Function 08, "Read measurement block"
- Switch ON ignition.
- Connect VAG 1551 Scan Tool (ST) and select function 08.

^ Display will appear as shown:

Read measurement block 1
1 2 3 4

- Slowly open throttle until wide open. While opening, observe angle display in channel 3.

NOTE: Numerical display value must increase uniformly over the entire opening range.

- Press --> button.
- Press 0 and 6 buttons to select function 06 "end data transfer".
- Press Q button to enter input.
- If displayed value does NOT increase uniformly:

- Perform electrical testing. Refer to Diagnostic Charts / Electrical Test Steps (ECM Pinout) / Test Steps 15, 34 and 35 and/or 31, 40 and 41. Testing and Inspection
- If necessary, replace Throttle Position sensor (G69).