CR-V - DTC Troubleshooting: P0135 (41), P1166 (41)
DTC P1135: A/F Sensor (Sensor 1) Heater Circuit Malfunction*
DTC P1166: A/F Sensor (Sensor 1) Heater Circuit Malfunction
NOTE: Information marked with an asterisk (*) applies to '04 model.
1. Reset the ECM/PCM.
2. Start the engine.
Is DTC P1166 (P0135)* indicated?
YES - Go to step 3.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose
terminals at the A/F sensor (Sensor 1) and the ECM/PCM.■
3. Measure voltage between ECM/PCM connector terminals A1 and A24, 30 seconds after the ignition switch is turned ON
(II).
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 4.
4. Measure voltage between ECM/PCM connector terminals A22 and A24.
Is there battery voltage?
YES - Go to step 5.
NO - Go to step 9.
5. Turn the ignition switch OFF.
6. Disconnect ECM/PCM connector A (31P).
7. Turn the ignition switch ON (II).
8. Connect ECM/PCM connector terminal E8 to body ground with a jumper wire, then measure voltage between ECM/PCM
connector terminals A1 and A24.
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 the ECM/PCM
(A1).■
9. Turn the ignition switch OFF.
10. Disconnect ECM/PCM connector A (31P) and the A/F sensor (sensor 1) 4P connector.
11. 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 relay, A/F sensor (Sensor 1), and
the ECM/PCM (A22).■
NO - Go to step 12.
12. Turn the ignition switch ON (II).
13. Measure voltage between ECM/PCM connector terminals E8 and A24.
Is there battery voltage?
YES - Repair open in the wire between the ECM/PCM (A22) and the A/F sensor (Sensor 1)
or A/F sensor relay.■
NO - Go to step 14.
14. Check the following fuses:
• No. 14 OPTION (40A) fuse in the under-hood fuse/relay box.
• No. 4 ACG (10A) fuse in the under-dash fuse/relay box.
• No. 15 +B LAF (A/F) HEATER (20A) in the 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 15.
15. Check for continuity in the wires between the A/F sensor relay 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.■
