- Preliminary Information

This section is used to find the correct test procedure for a given symptom. The symptoms and actions in this section are Emission related only. For further diagnostics regarding ignition systems and any electronic engine controls components, see Computers and Control Systems. Always use the "Flow of Diagnosis" for the proper testing sequence. Verify the correct system application to ensure that the vehicle has the given component(s).


NOTE: Except when attempting to diagnose a cold driveability problem, it is essential that the vehicle be properly warmed up to operating temperature. Vehicle should be driven for 10 to 20 minutes, to ensure that all systems are functioning during diagnosis. If this is not achieved, the catalytic converter and feedback systems will not function as designed. Resulting in inaccurate tests.