Throttle Position Sensor: Testing and Inspection

Throttle Position (TP) Sensor, Checking

Function
Both the Throttle Position (TP) sensor -G79- and Accelerator Pedal Position Sensor 2 -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.

Recommended special tools and equipment
- V.A.G 1526 multimeter or V.A.G 1715 multimeter
- V.A.G 1594 connector test kit
- Wiring diagram

Test requirements







- The respective fuses of Motronic Engine Control Module (ECM) -J220- must be OK.
- Battery voltage must be at least 11.5 volts.
- All electrical consumers such as: lights and rear window defroster must be switched off.
- Parking brake must be engaged or else day time driving lights will be switched on.
- For vehicles with automatic transmission, selector lever must be in position -P- or -N-
- If vehicle is equipped with an A/C system, it must be switched off.
- Ground (GND) connections between engine and chassis must be OK.

Test sequence

NOTE: When servicing terminals in the harness connector for the Throttle Position (TP) Sensor, use only gold-plated terminals.

- Remove footwell cover (driver's side).
- Disconnect 6-pin connector from Throttle Position (TP) Sensor.
- Switch ignition on.

Checking voltage supply and wiring to control module







- Connect multimeter with test leads to the following terminals connector for voltage measurement.

Terminal 1 + Ground (GND)
Terminal 1 + 5
Terminal 2 + Ground (GND)
Terminal 2 + 3

Specified value: at least 4.5 V

- Switch ignition off.

If specified values are not obtained:
- Check wires to control module according to wiring diagram.

Check wires to control module
- Connect test box to control module wiring harness. connect test box for wiring test. Test Box, Connecting For Wiring Test







- Check wires between test box and 6-pin connector to Engine Control Module (ECM) for open circuit according to wiring diagram.

Terminal 1 + socket 72
Terminal 2 + socket 73
Terminal 3 + socket 36
Terminal 4 + socket 35
Terminal 5 + socket 33
Terminal 6 + socket 34

Wire resistance: max. 1.5 Ohms

- Check wires for short circuit to each other, to vehicle Ground (GND) and to B+.

Specified value: Infinite Ohms

- Erase DTC memory of Engine Control Module (ECM). Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

If no malfunction is detected in the wiring and if the voltage supply was OK:
- Replace Throttle Position (TP) sensor.
- Erase DTC memory of Engine Control Module (ECM). Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes