Test Description
WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
The number below refer to the step number on the diagnostic procedure.
- 2
Whenever DTC P0108 is present, verify that no misfire is present by viewing the misfire counters. DTC P0108 may set as a result of a misfire. - 3
Inspect wiring for proper connections, pinches, and cuts, clean and tight PCM grounds, vacuum hoses for splits, kinks and proper connections as shown on the vehicle emission information label. Inspect thoroughly for any type of leak or restriction. - 4
This step determines if the Misfire DTC is the result of a hard malfunction or an intermittent condition. - 6
If the misfire is not present, operate the vehicle under the conditions found in the Freeze Frame data in order to detect the misfire. Depending on the engine load, the conditions may have to be maintained for up to 20 seconds. If the misfire accumulators start to increment, the misfire is present. A history misfire counter will record the number of misfires that occur until the DTC is cleared. The current counter must count a total of at least 195 misfires before the history counter begins storing the misfire information. - 10
No spark on one coil may be caused by an open secondary circuit. Therefore, the coils secondary resistance should be checked. - 13
Use the injector test light to test the harness wiring and to test for PCM control of the injectors. - 14
Perform the Fuel Inj Coil Test on the misfiring cylinder only. - 16
This step determines if the injector driver circuit is shorted to ground or voltage, or if the PCM is malfunctioning. - 22
Replace any spark plugs that are worn, cracked or fouled. - 27
Since voltage is supplied to injector on a single circuit before the injector harness, the malfunction may only be a poor connection or an open in injector harness. An open before the harness may result in a Cranks But Does Not Run complaint. - 28
A basic engine problem that affects only a single cylinder, such as valve train, compression, etc., is possible at this point.