DTC Troubleshooting: P1157 (48)
DTC P1157:
 A/F Sensor (Sensor 1) AFS 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 to ON (II).
  1. Clear the DTC with the HDS.
  1. Start the engine, and wait 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/PCM.■
  1. Turn the ignition switch to LOCK (0).
  1. Jump the SCS line with the HDS.
  1. Disconnect the A/F sensor (Sensor 1) 4P connector.
  1. Disconnect ECM/PCM connector C (49P).
  1. Check for continuity between A/F sensor (Sensor 1) 4P connector terminal No. 1 and ECM/PCM connector terminal C29.
Is there continuity?
YES -
Go to Step 10 .
NO -
Repair open in the wire between the ECM/PCM (C29) and the A/F sensor (Sensor 1), then go to Step 12 .