Starter Motor Interlock (+50)

Fault symptom
The starter motor does not work.
The alarm is not activated in the start position with the anti-theft alarm armed.
The starter motor runs at different ignition switch positions.


Important: If the LED flashes, the car may be self-immobilized.







Diagnostic procedure
1 Check the fuses
Check the Maxi 2 fuse and fuse 36. Also check that the fuses are live.
Connect the test lamp to:
- The Maxi 2 fuse and a good ground. The test lamp should light up.
- Fuse 36 and a good ground.
The lamp should light up when the ignition switch is turned to the "ST" position (+50).
Does it light up?
[YES] Continue with point 2.
[NO] Continue fault diagnosis as described in Service Manual 3:2 "Electrical system, +30 power supply" and "Starting system







2 Check the power supply (+50 circuit)
- Unplug connector H33-3.
- Connect the test lamp to pin 33 of connector H33-3 and a good ground.
- Turn the ignition switch to the "ST" position (+50).
The test lamp should light up.
Does it light up?
[YES] Continue with point 3.
[NO] Proceed to point 10.

3 Check the starting system
- Connect a jumper lead between pins 33 and 32 of connector H33-3.
- The gear lever should be in neutral on cars with a-manual gearbox (including Sensonic) and the selector lever in position "P" on cars with automatic transmission.
- Turn the ignition switch to the "ST" -position (+50).
The starter motor should run.
Is it running?
[YES] Continue with point 4.
[NO] Proceed to point 11.







4 Check the starter relay's contacts
- Plug in connector H33-3.
- Unplug the starter relay.
- Connect a jumper lead between pins 30 and 87 of the starter relay socket.
The starter motor should run.
Is it running?
[YES] Proceed to point 8.
[NO] Continue with point 5.

5 Check the starter relay's power supply (+30 circuit)
Connect the test lamp to pin 30 of the starter relay socket and a good ground.
The test lamp should light up.
Does it light up?
[YES] Continue with point 6.
[NO] Proceed to point 7.






6 Check the wiring connected to the starter motor
Check the wiring harness for continuity between pin 87 of the starter relay socket and pin 50 of the starter motor.
The resistance should be < 1 ohm.
Is the resistance OK?
[YES] Continue fault diagnosis as described in "Starting and Charging".
[NO] Check and repair or replace- the wiring, including connectors.

7 Check the wiring connected to the Maxi 2 fuse.
Connect the test lamp to the Maxi 2 fuse and a good ground.
The test lamp should light up.
Does it light up?
[YES] Check and repair or replace the wiring, including crimped connections.
[NO] Continue fault diagnosis as described in "+30 power supply".







8 Check the starter relay's power supply (+50 circuit)
- Connect the test lamp to pin 86 of the starter relay socket and a good ground.
- The gear lever should be in neutral on cars with a manual gearbox (including Sensonic) and the selector lever in position "P" on cars with automatic transmission.
- Turn the ignition switch to the "ST" position (+50).
The test lamp should light up.
Does It light up?
[YES] Continue with point 9.
[NO] Proceed to point 12.

9 Check the starter relay's connection to ground
Connect the test lamp to pins 85 and 30 of the starter relay socket.
The test lamp should light up.
Does it light up?
[YES] Change the starter relay.
[NO] Check and repair or replace the wiring, including grounding point G33S.







10 Check the wiring connected to fuse 36
- Connect the test lamp to fuse 36 and a good grounding point.
- Turn the ignition switch to the "ST" position (+50).
The test lamp should light up.
Does it light up?
[YES] Check and repair or replace the wiring.
[NO] Continue fault diagnosis as described in Service Manual 3:2 "Electrical system, Starting system".

11 Check the wiring connected to the electronic control module
- Unplug the control module.
- Check the wiring harness for continuity between
- connector H33-3 (pin 33) and the electronic control module (pin 20.
- connector H33-3 (pin 32) and the electronic control module (pin 8.
The resistance should be < 1 ohm.
Is the resistance OK?
[YES] Proceed to point 13.
[NO] Repair or replace the wiring harness.







12 Check the wiring connected to the starter relay
- Cars with automatic transmission: Continue fault diagnosis as described in "Automatic transmission".
- Cars with a manual gearbox: Check the wiring harness for continuity between pin 32 of connector H33-3 and pin 86 of the starter relay socket.
The resistance should be < 1 ohm.
Is the resistance OK?
[YES] Continue with point 13.
[NO] Repair or replace the wiring harness.

13 Final test
Start the car and check to see if the fault symptom persists.
Does the trouble persist?
[YES] Continue as described in "Before Changing The Electronic Control Module".
[NO] The remedial measures taken were correct or the fault is of intermittent nature.