DTC Troubleshooting
DTC Troubleshooting: P1157
DTC P1157:
A/F Sensor (Sensor 1) Circuit High Voltage
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
1. Turn the ignition switch to ON (II).
2. Clear the DTC with the HDS.
3. Start the engine, and wait at 1 minute.
4. Check for Pending or Confirmed 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 to LOCK (0).
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 PCM connector terminal C29 and A/F sensor (Sensor 1) 4P connector terminal No. 1.
Is there continuity?
YES -
Go to step 10.
NO -
Repair an 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 PCM connector terminal C30 and A/F sensor (Sensor 1) 4P connector terminal No. 2.
Is there continuity?
YES -
Go to step 11.
NO -
Repair an 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) A/F Sensor Replacement.
12. Reconnect all connectors.
13. Turn the ignition switch to ON (II).
14. Reset the PCM with the HDS.
15. Do the PCM idle learn procedure PCM Idle Learn Procedure.
16. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P1157 indicated?
YES -
Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the PCM, then go to step 1. If the connections and the terminals are OK, go to step 18.
NO -
Go to step 17.
17. Monitor the OBD STATUS for DTC P1157 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 16, go to the indicated DTC's troubleshooting.�
NO -
If the HDS 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 HDS indicates NOT COMPLETED, keep idling until a result comeson.
18. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
19. Start the engine, and let it idle.
20. Check for Pending or Confirmed 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 -
Go to step 21.
21. Monitor the OBD STATUS for DTC P1157 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?
YES -
If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs were indicated in step 20, go to the indicated DTC's troubleshooting.�
NO -
If the HDS 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 HDS indicates NOT COMPLETED, keep idling until a result comes on.