DTC P1166: A/F Sensor (Sensor 1) Heater Circuit Malfunction
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 C101 (located under the right side of
the dash), C401 (located under the left side of the dash), C402
(located under under the left side of the dash) the A/F Sensor relay,
the A/F Sensor (Sensor 1) and the ECM/PCM.
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.
Is there battery voltage?
YES - Update the ECM/PCM if it does not have the latest software,
or substitute a known-good ECM/PCM, then recheck. If the
symptom/indication goes away with a known-good ECM/PCM, replace the
original ECM/PCM.
NO - Go to step 5.
Is there battery voltage?
YES - Go to step 6.
NO - Go to step 10.
what does the code p1166 - 94729649
Is there battery voltage?
YES - Update the ECM/PCM if it does not have the latest software,
or substitute a known-good ECM/PCM, then recheck. If the
symptom/indication goes away with a known-good ECM/PCM, replace the
original ECM/PCM.
NO - Repair open or short in the wire between the A/F Sensor (Sensor 1) and ECM/PCM (A1).
Is there continuity?
YES - Repair short in the wire between the A/F Sensor relay, A/F Sensor (Sensor 1) and ECM/PCM (A22).
NO - Go to step 13.
Is there battery voltage?
YES - Repair open in the wire between the ECM/PCM (A22) and the A/F Sensor (Sensor 1).
NO - Go to step 15.
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.
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