- Preliminary Information

This section is used to find the correct test procedure for a given symptom. The symptom or actions in this section are emission related only. Refer to COMPUTERIZED ENGINE CONTROLS for complete Diagnosis By Symptom for Computerized Engine Controls. Always use the Flow of Diagnosis for proper testing sequence. Verify the correct system application to ensure that the vehicle has the given component(s).

Before proceding to the appropriate symptom perform the following inspection:

NOTE: It is essential that the vehicle has been properly warmed up and is at operating temperature (except when attempting to diagnosis a cold driveablity problem). The catalytic convertor and feedback systems will not function as designed if this is not achieved. Failure to do so will result in inaccurate test results.