DTC Troubleshooting

DTC P2628: Rear A/F Sensor (Bank 1, Sensor 1) LABEL Circuit High Voltage
DTC P2631: Front A/F Sensor (Bank 2, Sensor 1) LABEL Circuit High Voltage

NOTE:
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
- Information marked with an asterisk (*) applies to the front bank (Bank 2).

1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle for 2 minutes.
4. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P2628 and/or P2631* indicated?

YES - Go to step 5.

NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM.

5. Turn the ignition switch to LOCK (0).
6. Jump the SCS line with the HDS.
7. Disconnect the A/F sensor (Sensor 1) 8P connector.
8. Disconnect PCM connector C (49P).
9. Check for continuity between A/F sensor (Sensor 1) 8P connector terminal No. 7 and PCM connector terminal C13(C29)*.






Is there continuity?

YES - Go to step 10.

NO - Repair open in the wire between the PCM (C13 (C29)*) and the A/F sensor (Sensor 1), then go to step 15.

10. Check for continuity between A/F sensor (Sensor 1) 8P connector terminal No. 6 and PCM connector terminal C15.






Is there continuity?

YES - Go to step 11.

NO - Repair open in the wire between the PCM (C15) and the A/F sensor (Sensor 1), then go to step 15.

11. Reconnect PCM connector C (49P).
12. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle for 2 minutes.
13. Measure the voltage between A/F sensor (Sensor 1) 8P connector terminal No. 7 to body ground.






Is there about 5 V?

YES - Go to step 14.

NO - Go to step 20.

14. Replace the A/F sensor (Sensor 1).
15. Reconnect all connectors.
16. Turn the ignition switch to ON (II).
17. Reset the PCM with the HDS.
18. Do the PCM idle learn procedure. Programming and Relearning
19. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P2628 and/or P2631* indicated?

YES - Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM, then go to step 1.

NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.

20. Turn the ignition switch to LOCK (0).
21. Reconnect all connectors.
22. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
23. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P2628 and/or P2631* indicated?

YES - Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. If the PCM was substituted, go to step 1.

NO - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.