P1166

DTC P1166: A/F Sensor (Sensor 1) Heater Circuit Electrical Problem-'00-01 M/T models

1. Reset the ECM.
2. Start the engine.

Is DTC P1166 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 8P connector from the A/F sensor (Sensor 1)




5. At the sensor side, measure resistance between the A/F SENSOR (Sensor 1) 8P connector terminals No.1 and No.2.

Is there 2 - 13 Ohms ?

YES - Go to step 6.

NO - Replace the A/F sensor (Sensor 1).




6. Check for continuity between each terminal at the A/F sensor (Sensor 1) 8P connector and body ground.

Is there continuity?

YES - Replace the A/F sensor (Sensor 1).

NO - Go to step 7.




7. Check for continuity between the A/F sensor (Sensor 1) 8P connector terminals No.1 and No.3, No.4, No.6, No.7 and No.8 individually.

Is there continuity?

YES - Replace the A/F sensor (Sensor 1).

NO - Go to step 8.

8. Start the engine, and let it idle.




9. At the wire harness side, measure voltage between the A/F sensor (Sensor 1) 8P connector terminal No.1 and body ground.

Is there more than 5.0 V?

YES - Go to step 15.

NO - Go to step 10.

10. Turn the ignition switch OFF.
11. Disconnect ECM connector D (16P).




12. Check for continuity between ECM connector terminal D5 and body ground.

Is there continuity?

YES - Repair short in the wire between the ECM (D5) and the A/F sensor (Sensor 1).

NO - Go to step 13




13. Connect ECM connector terminal D5 to body ground with a jumper wire.




14. Check for continuity between the A/F Sensor (Sensor 1) 8P connector terminal No.1 and body ground.

Is there more than 5.0 V?

YES - Substitute a known-good ECM and recheck. If symptom/indication goes away, replace the original ECM.

NO - Repair open in the wire between the ECM (D5) and the A/F sensor (Sensor 1).




15. Measure voltage between the A/F sensor (Sensor 1) 8P connector terminals No.1 and No.2.

Is there more than 5.0 V?

YES - Substitute a known-good ECM and recheck. If symptom/indication goes away, replace the original ECM.

NO - Repair open in the wire between the A/F sensor (Sensor 1) and G101.