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.
- Start engine and allow it to reach operating temperature. Operate vehicle within, CODE ENABLE CRITERIA . On scan tool, monitor DTC information. If scan tool indicates DTC P0133 FAILED THIS IGNITION, go to next step. If scan tool display is not as specified, check for an intermittent problem. See DIAGNOSTIC AIDS .
- If scan tool also displays DTC P0153, P1133, P1134, P1153 or P1154 FAILED THIS IGN, go to step 11. If scan tool does not display these DTCs, go to next step.
- Visually inspect exhaust system for leaks in exhaust pipe joints, gaskets or flange joints near Bank 1 HO2S No. 1. If leaks are found, go to next step. If no leaks are found, go to step 6.
- Repair any exhaust leaks as necessary. After repairs are complete, retest system beginning in step 2.
- Visually inspect Bank 1 HO2S No. 1 for proper installation. Check for corrosion on terminals. Check terminal tension at Bank 1 HO2S No. 1 and PCM harness connectors. If problem is found, go to step 11. If no problem is found, go to next step.
- Turn ignition off. Disconnect Bank 1 HO2S No. 1 4-pin harness connector. Bank 1 HO2S No. 1 is located in right exhaust pipe. Turn ignition on. Using DVOM, measure voltage between ground and Bank 1 HO2S No. 1 harness connector terminal No. 1 (Green wire). See Figure. Measure voltage between ground and Bank 1 HO2S No. 1 harness connector terminal No. 2 (Red wire). Voltage should be 3-4 volts at both measurements. If voltage is as specified, go to next step. If voltage is not as specified, leave harness connector disconnected and go to step 9.
- Using fused jumper wires, connect high and low signal circuits of Bank 1 HO2S No. 1 harness connector (PCM side) to ground. Turn ignition on. Using scan tool, monitor HO2S voltage parameter. If voltage parameter is less than 10 millivolts and immediately returns to about 450 millivolts when jumper wire is removed, go to step 11. If voltage parameter is not as specified, go to step 12.
- Inspect PCM connections and terminals for damage. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR under SELF-DIAGNOSTIC SYSTEM. If PCM connections and terminals are okay, go to next step.
- Repair open, short or grounded Bank 1 HO2S No. 1 high or low signal circuits. See WIRING DIAGRAMS article. After repair is complete, see VERIFYING VEHICLE REPAIR under SELF-DIAGNOSTIC SYSTEM.
- Replace Bank 1 HO2S No. 1. Before replacing sensor, verify that cause of sensor failure has been corrected (fuel contamination, improper use of RTV sealant, excessive engine oil consumption, etc.) 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.