Diagnosis & Repair Procedure
NOTE:
For better performance and results of this diagnostic procedure, usage of appropriate wiring diagram is recommended. See ENGINE PERFORMANCE
in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
NOTE:
Perform all voltage and resistance tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use an ohmmeter to isolate wiring harness shorts or opens.
- If engine system check has been performed, go to next step. If engine system check has not been performed, perform A-4: ENGINE SYSTEM CHECK under SYSTEM TESTS, then go to next step.
- Turn ignition switch to LOCK position. Check EVAP-CPV circuit. See EVAP CANISTER PURGE VALVE CIRCUIT under FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. If EVAP-CPV circuit is okay, go to next step. If EVAP-CPV circuit is faulty, go to step 4 .
- Perform FTP sensor component test. See FUEL TANK PRESSURE SENSOR under FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. If FTP sensor is faulty, replace FTP sensor and repeat DTC CONFIRMATION TEST . If FTP sensor is okay, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO-CODES article. After repair, repeat DTC CONFIRMATION TEST .
- Perform EVAP-CVV component test. See EVAP CANISTER VENT VALVE under FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. If EVAP-CVV is faulty, replace EVAP-CVV. After repair, repeat DTC CONFIRMATION TEST . If EVAP-CVV is okay, check EVAP-CVV circuits for open or short in Blue/Black wire and Purple/Red wire between EVAP-CVV and ECM. If short or open circuit is found, repair as necessary. If short or open circuit is not found, substitute ECM with a known good unit and repeat DTC CONFIRMATION TEST .