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 ECM.

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 ECM connector C (44P).




9. Connect A/F sensor (Sensor 1) 4P connector terminals No. 1 and No. 2 with a jumper wire.




10. Check for continuity between ECM connector terminals C29 and C30.

Is there continuity?

YES - Go to step 14.

NO - Go to step 11.

11. Remove the jumper wire from the A/F sensor (Sensor 1) 4P connector.




12. Connect A/F sensor (Sensor 1) 4P connector terminal No. 2 to body ground with a jumper wire.




13. Check for continuity between ECM connector terminal C29 and body ground.

Is there continuity?

YES - Repair open in the wire between the ECM (C30) and the A/F sensor (Sensor 1), then go to step 15.

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

14. Replace the A/F sensor (Sensor 1).
15. Reconnect all connectors.
16. Turn the ignition switch ON (II).
17. Reset the ECM with the HDS.
18. Do the ECM idle learn procedure.
19. 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 ECM, then go to step 1. If the connector and terminal fits are OK, go to STEP 21. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - Go to step 20.

20. 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 ECM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 18 and recheck.

21. Update the ECM if it does not have the latest software, or substitute a known-good ECM.
22. Start the engine.
23. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1157 indicated?

YES - If the ECM was updated, substitute a known-good ECM, then go to step 22. If the ECM was substituted, go to step 1.

NO - If no Temporary DTCs or DTCs are indicated, go to step 24. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

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

Does the screen indicate PASSED?

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

NO - If the screen indicates FAILED, go to step 1. If the ECM was updated, substitute a known-good ECM, then go to step 22. If the ECM was substituted, go to step 1. If the screen indicates NOT COMPLETED, let the engine idle until a result comes on.