P1157

DTC P1157: A/F Sensor (Sensor 1) Circuit Malfunction

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Start the engine, and wait 1 minute.
4. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1157 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 OFF.
6. Jump the SCS line with the HDS.
7. Disconnect the A/F sensor (Sensor 1) 4P connector.
8. Disconnect PCM connector C (44P).




9. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 2 and PCM connector terminal C29.

Is there continuity?

YES - Go to step 10.

NO - Repair open in the wire between the PCM (C29) and the A/F sensor (Sensor 1), then go to step 12.




10. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 1 and PCM connector terminal C30.

Is there continuity?

YES - Go to step 11.

NO - Repair open in the wire between the PCM (C30) and the A/F sensor (Sensor 1), then go to step 12.

11. Replace the A/F sensor (Sensor 1).
12. Reconnect all connectors.
13. Turn the ignition switch ON (II).
14. Reset the PCM with the HDS.
15. Do the PCM idle learn procedure.
16. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P1157 is indicated, check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM, then go to step 1. If the connector and terminal fits are OK, go to step18. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - Go to step 17.

17. Monitor the OBD STATUS for DTC P1157 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - Troubleshooting is complete.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 15 and recheck.

18. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
19. Start the engine.
20. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1157 indicated?

YES - If the PCM was updated, substitute a known-good PCM, then go to step 19. If the PCM was substituted, go to step 1.

NO - If no Temporary DTCs or DTCs are indicated, go to step 21. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

21. Monitor the OBD STATUS for DTC P1157 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM.

NO - If the screen indicates FAILED, go to step 1. If the PCM was updated, substitute a known-good PCM, then go to step 19. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, let the engine idle until a result comes on.