P0122

P0122
Throttle Position Sensor A Circuit - Low Input
Throttle Position (TP) Sensor - Entry Signal Too Low

P0123
Throttle Position Sensor A Circuit - High Input
Throttle Position (TP) Sensor - Entry Signal Too High

Function
The TP Sensor determines the position of the throttle valve. The TP Sensor is supplied with + 5 Volt through pin 53 of the Engine Control Module (ECM) and through pin 34 connected to ground. The TP Sensor signal voltage is between approximately 0.5 Volt to approximately 4.7 Volt, depending on the position of the throttle valve. The idle contact is generated from the voltage value that occurs during the load phase. The value for the wide open throttle contact is calculated from the value of the generated idle contact.

Diagnostic conditions
A fault is recognized and stored in memory when the voltage is above 4.85 Volt or below 0.2 Volt, when the engine speed is above 400 1/min.

Wiring Diagram.

Diagnostic procedure.

Check voltage supply to TP Sensor.
1. Connect adapter cable VW 1501 between disconnection of TP Sensor.
2. Switch ignition on.
3. Connect voltmeter to wire No. 1 (plus) and No. 2 (minus). Specified value: approx. 5 V.
4. Connect voltmeter to wire No.1 (plus) and No. 3 (minus) Specified value at closed throttle valve: approx. 0.5 V.
5. Depress accelerator pedal all the way. Throttle valve must be wide open. Specified value: approx. 4.7 V.

Check TP Sensor.
1. Remove connector for TP Sensor.
2. Connect ohmmeter to TP Sensor pin 1 and pin 2. Specified value: 1.6 - 2.4 kohms
3. Connect ohmmeter to 2 and pin 3 Specified value: 710 - 1380 ohms.

Check wiring from disconnection between TP Sensor and ECM for continuity or short circuit to B+ or ground.
1. Check wiring No. 1 of TP Sensor connector to ECM, pin 53, for continuity or short circuit to B+ or ground.
2. Check wiring No. 2 of TP Sensor connector to ECM, pin 34, for continuity or short circuit to B+ or ground.
3. Check wiring No. 3 of TP Sensor connector to ECM, pin 44, for continuity or short circuit to B+ or ground.