Fault Isolation Procedure
- Checking the control module's signal input for cylinders 1 + 2/cylinder bank 1:
- Unplug the connector: Ignition discharge module, Bank 2 (346F).
- Take out pin 4.
- Plug in the connector: Ignition discharge module, Bank 2 (346F).
- Start the engine and run it at idling speed.
- Contact ECM.
- Read value: Combustion Detection Cyl 3 + 4 / Bank 2.
If the diagnostic tool shows a reading of 100, go to next step, otherwise go to step 3.
- Checking the control module's signal input for cylinders 1 + 2/cylinder bank 1 (continued):
- Connect a jumper lead between pin 4 (which is loose) and a good grounding point.
- Read value: Combustion Detection Cyl 3 + 4 / Bank 2.
If the diagnostic tool shows a reading of 0, go to step 4, otherwise go to next step.
- Rectifying the lead: The lead from pin 4 of the female connector to pin 6 of the control module is faulty. Rectify the fault and go to step 5.
- Changing components: Change Ignition discharge module, Bank 2. When finished, go to next step.
- Final check:
- Clear the DTCs in all systems.
- Carry out a drive cycle: Drive the car at varying engine loads and engine RPM for 5 minutes.
- Evaluate the drive cycle: Check that the DTC has not recurred.
If the trouble code has recurred, the ECM is probably at fault and will need replacement. Replace with known-good ECM and retest. If no DTCs are present, then the steps taken to rectify the fault were correct.
Courtesy of SAAB-SCANIA OF AMERICA, INC.