Throttle Position Sensor - Below Lower Limit

P0122

Throttle Position Sensor - Below Lower Limit

Function
The TP sensor determines the position of the throttle valve. The TP sensor is supplied with + 5 V through pin 53 of the DME control module and connected to ground through pin 34. The output signal voltage of the TP sensor ranges from approx. 0.5 V to approx. 4.7 V, depending on the position of the throttle.
The idle contact is generated from the voltage value which results during the deceleration phase. The value for full load contact is calculated from the generated idle contact value.

Diagnosis conditions
A fault is detected and stored in the memory when the voltage drops below 0.15 V or exceeds 4.85 V and the engine speed is above 400 rpm.

P0122-P0123:

Wiring Diagram







Diagnosis Procedure







1 Check voltage supply to TP sensor.

1. Connect special tool 9616.
2. Connect voltmeter to pin 53 (positive) and pin 34 (negative).
Switch on the ignition.
Display: approx. 4.5 - 5 volts

2 Check TP sensor.

1. Connect special tool 9616 to wiring harness (DME control module connector).
2. Connect ohmmeter to pin 44 and pin 53.
Display: approx. 2.0 - 3.0 kohms

Fully depress accelerator pedal.
Display: approx. 0.7 - 1.4 kohms

If there is no display, check the throttle position sensor directly.

3 Check wiring from TP sensor to DME control module for continuity or short circuit to B+ or ground.

NOTE: The wires to the TP sensor are routed via connector X 59/2.

1. Separate disconnection point to TP sensor.
2. Connect special tool 9616 to wiring harness (DME control module connector).
3. Connect ohmmeter to disconnection point, pin 1, and special tool 9616, pin 34.
Display: 0 - 5 ohms

4. Connect ohmmeter to disconnection point, pin 2, and special tool 9616, pin 53.
Display: 0 - 5 ohms

5. Connect ohmmeter to disconnection point, pin 3, and special tool 9616, pin 44.
Display: 0 - 5 ohms

6. Connect ohmmeter to disconnection point, pin 2, and ground.
Display: Infinity ohm

7. Connect ohmmeter to disconnection point, pin 3, and ground.
Display: Infinity ohm

8. Connect voltmeter to disconnection point, pin 2, and ground.
Display: 0 V

9. Connect voltmeter to disconnection point, pin 3, and ground.
Display: 0 V

If battery voltage is indicated for points 8 and 9, check wiring harness for chafing and pinching damage.