Engine Fails to Start
Engine Fails To StartFault symptom
- Engine fails to start
Diagnostic procedure
1 Check the crankshaft position sensor and the DI control module
- Check fuse 14, fuel pump, and fuse 9 in the engine bay and change them as necessary.
- Run the starter motor.
Does the tachometer needle jump?
YES The crankshaft position sensor and D/APC control module are OK. Continue with point 2.
NO Continue with point 5.
2 Check the injectors
- Connect test lamp 86 11 857 to one of the injectors.
Test lamp flashing?
YES Listen for the sound of the fuel pump working when the starter motor is cranking the engine. If the fuel pump is working, continue with point 3.
NO Continue fault diagnosis as described in "LH System Diagnostics".
3 Check the ignition discharge module
- Connect test lamp 86 11 857 to pins 6 and 10 of the ignition discharge module connector or to pins 3 (black) and 4 (grey/red) of connector 123/H4-10.
The lamp should light up with the ignition switched on.
Did the test lamp light up?
YES Check and if necessary adjust the spark plugs and then continue with point 4.
NO Rectify the fault.
Note: The pins in connector 123/H4-9/H4-10 may have lost their springiness with poor contact and unreliable operation as a result. Check one pin at a time and rectify any defects.
Also check that slide-out of the pins in the ignition discharge module's 10-pin connector does not occur when the connector is plugged into the module.
WARNING: The electrical ignition system generates voltages of 40,000 V. Such voltages may be fatal to persons with a weak heart or those who have a pacemaker implant. In view of this, treat the ignition system with the respect it deserves.
Important: The ignition discharge module should be stood with the ignition coils facing downwards when testing is performed so that the transformer oil will provide good insulation in the high-tension part of the coils.
4 Check the ignition spark
- Use grounding cable 86 10 867 and test spark plug 86 11 386.
- Remove the fuel pump fuse (14).
- Run the starter motor or activate with ISAT scan tool command 450.
Observe spark plug burn-off when the ignition is switched off.
Is an ignition spark produced?
YES Check the fuel pressure. Carry out a compression test on the engine.
NO Check and if necessary repair or replace the wiring between control module and ignition discharge module. Change the ignition discharge module. Note that an adapter wiring harness will be needed when changing M92 and earlier ignition discharge modules because only the ignition discharge module version with electrical connections in the module is available as a spare part.
5 Check the power supply
Is the ignition discharge module supplied with power?
YES Check the crankshaft position sensor as described for "Diagnostic trouble codes 44360/24360" Diagnostic Trouble Code Routines and then continue with point 6.
NO Carry out fault diagnosis as described under "Main relay". Testing and Inspection
Is the control module connected to positive voltage and ground?
YES Continue with point 6.
NO Rectify the fault and proceed to point 6.
6 Final check
- Implementation of driving cycle:
Drive the car at varying engine loads and rpm for 5 minutes.
- Evaluation of driving cycle:
Does the fault recur?
YES Continue with "Before Control Module Replacement". Service and Repair
NO The steps taken to rectify the fault were correct.