Diagnosis & Repair Procedure
- If engine system check has been performed, go to next step. If engine system check has not been performed, go to A4: ENGINE SYSTEM CHECK under SYSTEM TESTS.
- Using scan tool, check for current or pending DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES . If DTCs other than DTC P0174 or P0175 is set, repair those DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no other DTC is set, go to next step.
- Inspect intake and exhaust systems for leaks. If any leaks are detected, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If intake and exhaust systems are okay, go to next step.
- Check fuel pressure. See B-3: FUEL PRESSURE INSPECTION under CIRCUIT TESTS in BASIC DIAGNOSTIC PROCEDURES article. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If fuel pressure is within specifications, go to next step.
- Check fuel injectors operation. See B-1: FUEL INJECTOR CIRCUIT INSPECTION under CIRCUIT TESTS in BASIC DIAGNOSTIC PROCEDURES article. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If fuel injectors are okay, go to next step.
- Check fuel lever sensor operation. See DTC P0461 . If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If fuel level sensor is okay, go to next step.
- Check MAF sensor circuit operation. See DTC P0101 test. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If MAF sensor circuit is okay, go to next step.
- Check ECT sensor circuit operation. See DTC P0125 test. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If ECT sensor circuit is okay, go to next step.
- Check HO2S No. 1 sensor circuit operation. See DTC P0138 OR DTC P0140 . If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If HO2S No. 1 sensor circuit is okay, go to next step.
- Substitute a known good ECM, and repeat DTC CONFIRMATION TEST . If DTC does not reset, testing is complete.