P1157

DTC P1157: A/F Sensor (Sensor 1) Circuit High Voltage-'02-03 M/T models

1. Reset the ECM.
2. Start the engine, and wait at least 2 minutes.

Is DTC P1157 indicated?

YES - Go to step 3.

NO - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the A/F Sensor (Sensor 1) and at the ECM.

3. Turn the ignition switch OFF.
4. Disconnect the A/F Sensor 4P connector, and ECM connector D (16P).




5. Connect ECM connector terminals D4, D10, and body ground with a jumper wire.




6. Check for continuity between the A/F Sensor (Sensor 1) 4P connector terminal No.1, No.2, and body ground individually.

Is there continuity?

YES - Go to step 7.

NO - Repair open in the wire between the A/F Sensor (Sensor 1) and the ECM (D4 or D10).

7. Substitute a known-good A/F Sensor (Sensor 1) and recheck.

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 original A/F Sensor (Sensor 1).