Diagnostic Procedure
NOTE:
Before performing testing procedures, check for any related Technical Service Bulletins (TSBs).
Diagnosis of computerized engine control system should be performed in the following order:
- Perform visual inspection. Most driveability problems in the engine control system result from faulty wiring, poor electrical connections or leaking air and vacuum hose connections. To avoid unnecessary component testing, perform a visual inspection before beginning DIAGNOSTIC TESTS .
- Ensure all mechanical engine systems other than computerized systems (i.e., compression, ignition, etc.) are operating properly. DO NOT proceed with testing unless all other problems have been repaired. If Malfunction Indicator Light (MIL) is on, see RETRIEVING DIAGNOSTIC TROUBLE CODES . For diagnosing DTCs, see appropriate DTC test under DIAGNOSTIC TROUBLE CODES .
- After repairs have been completed, clear DTC(s). See CLEARING DIAGNOSTIC TROUBLE CODES . Recheck system and verify repair is complete.