P1157
DTC P1157: A/F Sensor (Sensor 1) Circuit High Voltage1. Reset the ECM with the HDS.
2. Start the engine.
3. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1157 indicated?
YES - Go to step 4.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the ECM.
4. Turn the ignition switch OFF.
5. Disconnect the A/F sensor (Sensor 1) 4P connector and ECM connector D (16P).
6. Connect A/F sensor (Sensor 1) 4P connector terminals No.1 and No.2 with a jumper wire.
7. Check for continuity between ECM connector terminals D4 and D10.
Is there continuity?
YES - Go to step 10.
NO - Go to step 8.
8. Connect A/F sensor (Sensor 1) 4P connector terminal No.2 to body ground with a jumper wire.
9. Check for continuity between ECM connector terminal D4 and body ground.
Is there continuity?
YES - Repair open in the wire between the A/F sensor (Sensor 1) and the ECM (D10).
NO - Repair open in the wire between the A/F sensor (Sensor 1) and the ECM (D4).
10. Substitute a known-good A/F sensor (Sensor 1).
11. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1157 indicated?
YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
NO - Replace the A/F sensor (Sensor 1).