Throttle Position Sensor: Testing and Inspection

Throttle Position (TP) sensor, checking

Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test requirement







- The respective fuses of Motronic Engine Control Module (ECM) -J220- must be OK.







- Fuses -1, 2, 3, 4 and 7- in protective housing (plenum chamber, left) must be OK.
- Battery voltage must be at least 11.5 Volts.
- All electrical consumers such as, for example, lights and rear window defroster must be switched off.
- Parking brake must be engaged or else daylight 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.

Function
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


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 to the following connector terminals 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:
- 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 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

- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinity Ohms
- Erase DTC memory of Engine Control Module (ECM), 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, item 4 .
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes