Diagnostic Procedures
- Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
- Operate engine for one minute. Monitor scan tool display. If any current counters are incrementing, go to next step. If no current counters are incrementing, problem is intermittent. See DIAGNOSTIC AIDS .
- If a particular counter is dominant, see DTC P0301-P0306: SPECIFIC CYLINDER MISFIRE DETECTED . If a particular counter is not dominant, go to next step.
- Ensure that a MAF or EGR solenoid DTCs are not set. If any of this DTC is set, diagnose affected DTC(s) first. If no other DTCs are set, perform fuel pressure test, injector leakdown test or injector balance test. Check faulty spark plugs, internal mechanical engine failure, faulty injector or for fuel quality. See appropriate SYSTEM & COMPONENT TESTING article.