9000 L4-1985cc 2.0L DOHC (1986)
Engine Control Module: Service and Repair
Before Control Module Replacement
Before Control Module Replacement
When all tests have been carried out according to the relevant diagnostics procedure or by manual fault diagnosis without any faults having been
found, it is natural to assume that the control module is at fault.
Therefore, go through the following points carefully before definitely pinpointing the LH control module as the cause of the fault.
1 Check once again that every single point in the fault diagnosis procedure for the relevant diagnostic trouble code has been carried out.
2 Study the wiring diagram of the circuit in question and make sure you understand how it works.
3 Check all grounding points. If you have already done so, do it once again. Check that power ground and sensor are mechanically and electrically
separate.
4 Check the power supply for the control module.
5 Check the input and output signals and compare the readings with the tables for the LH system in question.
6 Be restrictive with control module replacement. Unnecessary control module replacement represents a major expense for the customer. Think of
every possible cause of the fault before changing the control module.
7 If the fault still persists, the LH control module will have to be changed.
