P1166
DTC P1166: A/F Sensor (Sensor 1) Heater Circuit Malfunction-'02-03 M/T models and CVT model1. 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 C102 (located under the right side of the dash) the A/F Sensor relay, the A/F Sensor (Sensor 1) and the ECM.
3. Check the following fuse:
- No.16 (30 A) fuse in under-hood fuse/relay box.
- No.14 (30 A) fuse in under-dash fuse/relay box.
- No.4 (7.5 A) in under-dash fuse/relay box.
Are any of the fuses blown?
YES - Repair short in the wire between the A/F Sensor relay and the fuses.
NO - Go to step 4.
4. Measure voltage between ECM connector terminals D5 and B20, 30 seconds after the ignition switch is turned ON (II).
Is there battery voltage?
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 - Go to step 5.
5. Measure voltage between ECM connector terminals D11 and B20.
Is there battery voltage?
YES - Go to step 6.
NO - Go to step 10.
6. Turn the ignition switch OFF.
7. Disconnect the ECM connector A (32P).
8. Turn the ignition switch ON (II).
9. Connect ECM connector terminal All to body ground with a jumper wire, then measure voltage between ECM connector terminals D5 and B20.
Is there battery voltage?
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 - Repair open or short in the wire between A/F Sensor (Sensor 1) and ECM (D5).
10. Turn the ignition switch OFF.
11. Disconnect the ECM connector D (16P) and the A/F Sensor (Sensor 1) 4P connector.
12. Check for continuity between the A/F Sensor (Sensor 1) 4P connector terminal No.4 and body ground.
Is there continuity?
YES - Repair short in the wire between the A/F Sensor relay, A/F Sensor (Sensor 1) and ECM (D11).
NO - Go to step 13.
13. Turn the ignition switch ON (II).
14. Measure voltage between ECM connector terminals A11 and B20.
Is there battery voltage?
YES - Repair open in the wire between the ECM (D11) and the A/F Sensor (Sensor 1).
NO - Go to step 15.
15. Check for continuity in the wires between the A/F Sensor and the fuses.
Is there continuity?
YES - The wires are OK. Replace the A/F Sensor relay.
NO - Repair open in the wire between the A/F Sensor relay and the fuses.