It may not be the sensor. It indicates the heater circuit, which is electrical problem, not the sensor. This is the upstream sensor (Sensor 1) , the one on the exhaust manifold.
DTC P1166: A/F SENSOR (SENSOR 1) HEATER CIRCUIT MALFUNCTION
1.Reset the ECM/PCM (***Don't worry about this***).
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 under-hood fuse/relay box), the A/F Sensor relay, the A/F Sensor (Sensor 1) and the ECM/PCM. ***Still, you want to check the connection***
3.Check the following fuses:
à   POWER SEAT (20A) fuse in the under-hood fuse/relay box.
à   No. 4 ECU (ECM/PCM) CRUISE CONTROL (15A) fuse in the driver's under-dash fuse/relay box.
à   No. 6 LAF HEATER (20A) in the passenger's under-dash fuse/relay box.
4.Measure voltage between ECM/PCM connector terminals B19 and B20, 30 seconds after the ignition switch is turned ON (II).
Is there battery voltage?
YES - Substitute a known-good ECM/PCM and recheck. If the symptom/indication goes away, replace the original ECM/PCM. NO - Go to step 5
5.Measure voltage between ECM/PCM connector terminals C13 and B20.
6.Turn the ignition switch OFF.
7.Disconnect ECM/PCM connector B (25P).
8.Turn the ignition switch ON (II).
9.Connect ECM/PCM connector terminal B16 to body ground with a jumper wire, then measure voltage between ECM/PCM connector terminals B19 and B20.
Is there battery voltage?
YES - Substitute a known-good ECM/PCM and recheck. If the symptom/indication goes away, replace the original ECM/PCM. NO - Repair open or short in the wire between A/F Sensor (Sensor 1) and ECM/PCM (B19).
10.Turn the ignition switch OFF.
11.Disconnect ECM/PCM connector B (25P) and the A/F Sensor (Sensor 1) 4P connector.
12.Check for continuity between A/F Sensor (Sensor 1) 4P connector terminal No. 3 and body ground.
Is there continuity?
YES - Repair short in the wire between the A/F Sensor (Sensor 1) and ECM/PCM (B19). NO - Go to step 13.
13.Turn the ignition switch ON (II).
14.Measure voltage between ECM/PCM connector terminals B16 and B20
Is there battery voltage?
YES - Repair open in the wire between the ECM/PCM (C13) and the A/F Sensor (Sensor 1) or Secondary HO2S (Sensor 2). NO - Go to step 15.
15.Check for continuity in the wires between 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.
I'll email you the diagnostic for P01167.
Monday, May 11th, 2009 AT 10:25 PM
