DTC Troubleshooting: P1157 (48)
DTC P1157:
 A/F Sensor (Sensor 1) AFS Line 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 ON (II).
  1. Clear the DTC with the HDS.
  1. Start the engine, and wait for 1 minute.
  1. 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.■
  1. Turn the ignition switch OFF.
  1. Jump the SCS line with the HDS.
  1. Disconnect the A/F sensor (Sensor 1) 4P connector.
  1. Disconnect ECM connector C (44P).
  1. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 2 and ECM connector terminal C29.
Is there continuity?
YES -
Go to Step 10 .
NO -
Repair open in the wire between the ECM (C29) and the A/F sensor (Sensor 1), then go to Step 12 .
  1. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 1 and ECM connector terminal C30.
Is there continuity?
YES -
Go to Step 11 .
NO -
Repair open in the wire between the ECM (C30) and the A/F sensor (Sensor 1), then go to Step 12 .
  1. Reconnect all connectors and the battery.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Check for Temporary DTCs or 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 ECM, then go to Step 1 . If the connector and terminal fits are OK, go to Step 18 .
NO -
Go to Step 17 .
  1. Monitor the OBD STATUS for DTC P1157 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in Step 16 , go to the indicated DTC's troubleshooting.■
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 15 .
  1. Start the engine.
  1. 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 19 . If the ECM was substituted, go to Step 1 .
NO -
Go to Step 21 .
  1. 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. If any other Temporary DTCs or DTCs were indicated in Step 20 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, go to Step 1 . If the ECM was updated, substitute a known-good ECM, then go to Step 19 . If the ECM was substituted, go to Step 1 . If the screen indicates NOT COMPLETED, keep idling until a result comes on.