1. Pull off plug I on the alarm control unit.
2. Pull off the DmE plug.
3. Ohmmeter at plug I, alarm control unit pin 23, and DmE plug pin 88.
Display: < 5 ohms
Note:
The line runs via plug connection X 3/1, pin 14.
4. Ohmmeter at plug I alarm control unit pin 23 and ground.
Display:
5. Voltmeter at plug I alarm control unit pin 23 and ground. Switch on the ignition.
Display: 0 Volts
If no fault can be detected, try replacing the alarm control unit. If the fault is still present, the DmE control unit is faulty.
Test Point 22
TEST POINT 22
Passenger Compartment monitoring Sensor, Ground Short
Fault Code 22
Fault Effect: No passenger compartment monitoring
Procedure
1. Pull off plug I on the alarm control unit.
2. Pull off the plug on the passenger compartment monitoring sensor.
3. Ohmmeter at plug I alarm control unit pin 24, and ground.
Display: infinity
If display < 5 ohms, check the wiring harness for pinches and chafing damage.
Test Point 23
TEST POINT 23
W-line (DmE Immobilizer) Positive Short
Fault Code 23
Procedure
2G1. Voltmeter at plug I alarm control unit pin 23 and ground. Switch on the ignition.
Display: 0 Volts
If no fault can be detected, try replacing the alarm control unit. If the fault is still present, the DmE control unit is faulty.
Test Point 24
TEST POINT 24
Control unit faulty
Fault Code 24
Fault Effect: No engine start possible
Procedure
Replace the control unit.