Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.
- Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
- Turn ignition on. Using scan tool, observe EVAP canister purge valve parameter. If parameter is about zero percent, problem is intermittent. See DIAGNOSTIC AIDS . If parameter is not as specified, go to next step.
- Turn ignition off. Disconnect EVAP canister purge valve 2-pin harness connector. EVAP valve is located on intake manifold below throttle body. Disconnect PCM Red 80-pin harness connector E-22. PCM is located at right rear of engine compartment. Check for open or short circuit in Red/Blue wire between EVAP canister purge valve and PCM. See WIRING DIAGRAMS article. If problem is found, go to next step. If no problem is found, go to step 5.
- Repair open or short circuit in Red/Blue wire between EVAP canister purge valve and PCM. After repair is complete, see VERIFYING VEHICLE REPAIR under SELF-DIAGNOSTIC SYSTEM.
- Using DVOM, measure resistance between EVAP canister purge valve pins. At 68°F (20°C) resistance should be 25-30 ohms. If resistance is as specified, go to step 7. If resistance is not as specified, go to next step.
- Replace EVAP canister purge valve. After repair is complete, see VERIFYING VEHICLE REPAIR under SELF-DIAGNOSTIC SYSTEM.
- Replace and reprogram PCM. See POWERTRAIN CONTROL MODULE REPLACEMENT under POWERTRAIN CONTROL MODULE. Use scan tool to clear DTC and verify repair.