112 Camshaft Position Sensor 1 - Signal Implausible

P0341

112 Camshaft Position Sensor 1 - Signal Implausible

Function
The signal from CMP sensor 1 identifies the first cylinder. If both the crankshaft position (reference mark) signal and the CMP sensor signal coincide, this signifies the ignition timing for cylinder 1.
The recognition of cylinder 1 is necessary for the purpose of sequential fuel injection and knock control.

Diagnosis conditions
- Engine running

P0341 - P0343:

Wiring Diagram







Diagnosis Procedure










1 Check power supply to CMP sensors.
1. Remove connector of CMP sensor 1.
2. Switch on the ignition.
3. Connect voltmeter to pin 1 (negative) and pin 3 (positive).

Display: approx. 5 V

2 Check power supply wiring for continuity.
1. Remove connector of CMP sensor 1.
2. Connect special tool 9637 to wiring harness (DME control module connector).
3. Connect ohmmeter to special tool 9637, pin III/7, and to CMP sensor connector 1, pin 3.

Display: 0 - 5 ohms

4. Connect ohmmeter to special tool 9637, pin III/17, and to CMP sensor connector 1, pin 1.

Display: 0 - 5 ohms

3 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.

4 Check CMP sensor signal.







1. Connect special tool 9637.
2. Connect engine tester. Using special input, connect positive cable to pin III/20, negative cable to pin III/17.
3. Start the engine.

The display pictured opposite should appear on the oscilloscope:

5 Check signal wire from DME control module, pin III/20, to CMP sensor.
1. Connect special tool 9637 to wiring harness (DME control module connector).
2. Remove connector of CMP sensor.
3. Connect ohmmeter to special tool 9637, pin III/20, and to CMP sensor connector 1, pin 2.

Display: 0 - 5 ohms

6 Check signal wire from DME control module, pin III/20, to CMP sensor for short circuit to ground.
1. Connect special tool 9637 to wiring harness (DME control module connector).
2. Remove connector of CMP sensor.
3. Connect ohmmeter to special tool 9637, pin III/20, and ground.

Display: infinity ohms

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

7 Check signal wire from DME control module, pin III/20, to CMP sensor for short circuit to B+.
1. Connect special tool 9637 to wiring harness (DME control module connector).
2. Remove connector of CMP sensor.
3. Connect voltmeter to special tool 9637, pin III/20, and ground.

Switch on the ignition.
Display: 0 V

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