9000 Hatchback L4-2290cc 2.3L DOHC Turbo EFI (1994)
Engine Control Module: Service and Repair
Before Control Module Replacement
BEFORE REPLACING A CONTROL MODULE
When all the checks have been carried out in accordance with the diagnostic procedures programme for the diagnostic trouble code concerned or
through manual fault diagnosis without any fault having been detected, it is natural to assume that the control module is at fault.
You should carefully run through the following points before finally identifying the Trionic control module as the cause of the fault.
1. Check once more that all the items for checking in the fault diagnosis procedure for the relevant diagnostic trouble code have been carried out.
2. Study the wiring diagram of the relevant circuit and make sure you know how it works.
3. Check all grounding points. If you have already done this, do it once more. Check that power ground and sensor are mechanically and electrically
separated.
4. Check the voltage supply to the control module.
5. Experience of model year 1993 shows that 80% of all Trionic control modules returned for repair under warranty were in perfect working order.
Do not fit replacement control modules unnecessarily.
Control modules that are replaced without reason represent a sizeable cost item for Saab automobile and Saab dealers. Think through likely causes
of the fault before changing the control module.
When substituting a control model for testing purposes, always refit the correct control module.
6. If the original fault nevertheless persists, the Trionic control module must be replaced.
