DTC Troubleshooting: P0139 (65-3), P0141 (65-2)

DTC P0141 (65-2):  Secondary HO2S (Sensor 2) Heater Circuit Malfunction

1.Reset the ECM/PCM.

2.Start the engine.

Is DTC P0141 indicated?


YES - Go to 3.


NO - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the  secondary HO2S (Sensor 2) and at the  ECM/ PCM.n


3.Turn the ignition switch OFF.

4.Disconnect the secondary HO2S (Sensor 2) 4P connector.

5.At the secondary HO2S (Sensor 2) side, measure resistance between the HO2S 4P connector terminals No. 3 and No. 4.

 

Is there about 3.3 W?


YES - Go to 6.


NO - Replace the  secondary HO2S (Sensor 2).n

6.Check continuity between body ground and secondary HO2S (Sensor 2) 4P connector terminals No. 3 and No. 4 individually.

 

Is there continuity?


YES - Replace the  secondary HO2S (Sensor 2).n


NO - Go to 7.


7.Turn the ignition switch ON (II).

8.Measure voltage between secondary HO2S 4P connector terminals No. 3 and No. 4.

 

Is there battery voltage?


YES - Go to 9.


NO - Go to 14.


9.Turn the ignition switch OFF.

10.Disconnect the negative cable from the battery.

11.Disconnect ECM/PCM connector E (31P).

12.Reconnect the negative cable to the battery.

13.Check for continuity between ECM/PCM connector terminal E6 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the  ECM/ PCM (E6) and the  secondary HO2S (Sensor 2).n


NO - Substitute a known-good ECM/PCM and recheck . If symptom/indication goes away, replace the original  ECM/ PCM.n


14.Measure voltage between secondary HO2S (Sensor 2) 4P connector terminal No. 4 and body ground.

 

Is there battery voltage?


YES - Go to 15.


NO - Check the No. 4 ACG (10A) fuse in the under-dash fuse/relay box. If the fuse is OK, repair open in the wire between the  secondary HO2S (Sensor 2) and No. 4 ACG (10A) fuse.n

15.Turn the ignition switch OFF.

16.Reconnect the secondary HO2S (Sensor 2) 4P connector.

17.Disconnect the negative cable from the battery.

18.Disconnect ECM/PCM connector E (31P).

19.Reconnect the negative cable to the battery.

20.Turn the ignition switch ON (II).

21.Measure voltage between ECM/PCM connector terminal E6 and A5.

 

Is there 0.1 V or less?


YES - Repair open in the wire between the  ECM/ PCM (E6) and the  secondary HO2S (Sensor 2).n


NO - Substitute a known-good ECM/PCM and recheck . If symptom/indication goes away, replace the original  ECM/ PCM.n