Diagnosis & Repair Procedure
WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
- Perform DTC confirmation procedure. See DTC CONFIRMATION PROCEDURE under SELF-DIAGNOSTIC SYSTEM. Check for DTCs during KOEO and KOER self-test. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. If DTC P0156, P1157 or P1158 is present, go to next step. If DTC P0156, P1157 or P1158 are not present, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
- Disconnect left rear HO2S connector. Check for loose, damaged or corroded connector terminals. Repair as necessary, and go to next step. If connector terminals are okay, go to next step.
- Measure resistance between left rear HO2S connector Violet/Red wire and Red/Black wire terminals. If resistance is about 6 ohms, go to next step. If resistance is not about 6 ohms, replace left rear HO2S and go to step 9 .
- Turn ignition on. Measure voltage between ground and left rear HO2S harness connect terminal "C" (Red/Black wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open in Red/Black wire. See WIRING DIAGRAMS article. Go to step 9 .
- Measure voltage between ground and left rear HO2S harness connector terminal "D" (Violet/Red wire). If battery voltage is not present, go to next step. If battery voltage is present, repair short to power in Violet/Red wire. See WIRING DIAGRAMS article. Go to step 9 .
- Turn ignition off. Check for continuity between ground and left rear HO2S harness connect terminal "D" (Violet/Red wire). If continuity is not present, go to next step. If continuity is present, repair short to ground in Violet/Red wire. See WIRING DIAGRAMS article. Go to step 9 .
- Disconnect PCM connector. Check for loose, damaged or corroded connector terminals. Repair as necessary, and go to step 9 . If connector terminals are okay, go to next step.
- Check for continuity of Violet/Red wire between left front HO2S harness connector terminal "D" and PCM harness connector terminal No. 96. See Figure . If continuity is present, go to next step. If continuity is not present, repair open in Violet/Red wire. See WIRING DIAGRAMS article. Go to next step.
- Reconnect all connections. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Perform KOEO and KOER self-test. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. If DTC P0156, P1157 or P1158 is present, replace PCM and go to next step. See REMOVAL, OVERHAUL & INSTALLATION article. On vehicles equipped with immobilizer system, reprogram ignition key identification numbers. See COMPUTER RELEARN PROCEDURES - IMPORT article in GENERAL INFORMATION. If DTC P0156, P1157 or P1158 are not present, go to next step.
- Perform DTC confirmation procedure. See DTC CONFIRMATION PROCEDURE under SELF-DIAGNOSTIC SYSTEM. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to appropriate test.