402 Throttle Jacking Unit, Position Error - Signal Implausible

P1503

402 Throttle Jacking Unit, Position Error - Signal Implausible

Function
The throttle angle demanded by the DME control module is achieved by means of a digital position controller. The rapid and precise setting of the desired throttle position is of major importance for the quality of charging control.
In the event of a position error fault, the throttle angle measured by the potentiometers does not match the calculated throttle angle.

Diagnosis conditions
- Driving with changing pedal position

P1503:

NOTE: The vehicle is in emergency air function mode, i.e. the engine is turning at approx. 1200 rpm

Wiring Diagram







Diagnosis Procedure

Part 1:

Part 2:

1 Check wiring from DME control module, pin III/42, to throttle part for short circuit to B+.
1. Connect special tool 9637.
2. Connect voltmeter to pin III/42 and ground.
3. Switch on the ignition.

Display: 0 V

If battery voltage is displayed, check wiring harness for chafing and pinching damage.

2 Check wiring from DME control module, pin III/43, to throttle part for short circuit to B+.
1. Connect special tool 9637.
2. Connect voltmeter to pin III/43 and ground.
3. Switch on the ignition.

Display: 0 V

If battery voltage is displayed, check wiring harness for chafing and pinching damage.

3 Check wiring from DME control module, pin III/42, to throttle part for short circuit to ground.
1. Connect special tool 9637.
2. Connect voltmeter to pin III/42 and B+.
3. Switch on the ignition.

Display: 0 V

If battery voltage is displayed, check wiring harness for chafing and pinching damage.

4 Check wiring from DME control module, pin III/43, to throttle part for short circuit to ground.
1. Connect special tool 9637.
2. Connect voltmeter to pin III/43 and B+.
3. Switch on the ignition.

Display: 0 V

If battery voltage is displayed, check wiring harness for chafing and pinching damage.

5 Check wiring from DME control module, pin III/42, for short circuit to wire, pin III/43.







1. Connect special tool 9637 to wiring harness (DME control module connector).
2. Remove connector of throttle part.
3. Connect ohmmeter to pins III/42 and III/43.

Display: infinity ohms

If 0 - 5 ohms is displayed, check wiring harness for chafing and pinching damage.

6 Check resistance of motor actuator in throttle part.
1. Connect special tool 9637 to wiring harness (DME control module connector).
2. Connect ohmmeter to pins III/42 and III/43.

Display: 1.2 - 1.6 ohms at 20 °C.

7 Perform adaptation.
1. Switch on the ignition.
2. Wait one minute. Do not press the accelerator.
3. Switch off the ignition for at least 10 seconds.
4. Read out the fault memory.