Throttle Position Sensor: Testing and Inspection

Throttle Position (TP) Sensor, Checking

Special Tools and Equipment







- VAG1526A
- VAG1594A
- VAG1598/31
- VAS5051 with VAG5051/1

Both the Throttle Position (TP) sensor -G79- and the Sender -2- for accelerator pedal position -G185- are located at the accelerator pedal and communicate the driver's intentions to the ECM completely independently of each other. Both sensors are stored in one housing.

Test sequence
- Connect VAS5051 tester and select vehicle system "01 - Engine electronics". Ignition must remain switched on for this. Refer to "Scan Tool Testing/Scan Tool Connecting and Initial Checks/VAS 5051 Tester, Connecting and Selecting Functions" Testing and Inspection








Display on VAS5051:
- Select diagnostic function "08 - Read Measuring Value Block" in selection -1-.







Display on VAS5051:
1 - Enter display group Max. input value = 255
- Select function "062" in button field -2- for "display group number 062" and press Q button to confirm input.







Display on VAS5051:
- Check specified values for E-gas potentiometer voltages in display fields -3- and -4-.

Display Group 062:

- Observe display field 3 and 4.
- Slowly depress accelerator pedal completely.

Percent indication in display field 3 must rise uniformly. The tolerance range 12 to 97% is not used completely during this.
Percent indication in display field 4 must also rise uniformly. In the process, the tolerance range of 4 to 49% is not completely utilized.


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


- Press "08 - erase DTC memory" to end function <- button.

If indications do not resemble description:
- Check voltage supply and wire connections of sensor for accelerator pedal position. Testing and Inspection


Checking voltage supply of Throttle Position (TP) sensor
- Remove driver-side storage compartment.
- Disconnect harness connector for accelerator pedal position sensor.
- Switch ignition on.







- Connect multimeter for voltage measurement as follows:







If specified values are obtained:
- Also check signal wires.

If specified values are not obtained:
- Check wire connections from Engine Control Module (ECM) to sensors for accelerator pedal position.







Checking wire connections
- Connect VAG1598/31 test box at wiring harness to Engine Control Module (ECM), do not connect ECM. Refer to "Scan Tool Testing/Wire and Component Testing Using VAG1598/31 Test Box" Testing and Inspection







- Check the following wire connection for open circuit and short circuit to Ground (GND) and B+:
- Repair open circuit or short circuit if necessary.

If no malfunctions are found in wires:
- Replace accelerator pedal position sensor.