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

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Start the engine.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0141 indicated?

YES -Go to step 5.

NO -Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the ECM/PCM.
Turn the ignition switch to LOCK (0).
Check the No. B12 IMA (10 A) fuse in the under-dash fuse/relay box.
Is the fuse OK?

YES -Go to step 7.

NO -Repair a short in the wire between secondary HO2S (Sensor 2), the idle stop switch, the EVAP canister purge valve, the MAF sensor, and the No. B12 IMA (10 A) fuse. Also replace the No. B12 IMA (10 A) fuse, then go to step 23.
Remove the cowl cover and the under-cowl panel (see COWL COVER REPLACEMENT ).
Disconnect the secondary HO2S (Sensor 2) 4P connector.
At the secondary HO2S (Sensor 2) side, measure the resistance between secondary HO2S (Sensor 2) 4P connector terminals No. 3 and No. 4.

Fig 1: Measuring Resistance Between Secondary HO2S (Sensor 2) 4P Connector Terminals No. 3 And No. 4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there 5.4-7.3 Ω at room temperature (65-70°F, 18-21°C)?

YES -Go to step 10.

NO -Go to step 22.
At the secondary HO2S (Sensor 2) side, check for continuity between body ground and secondary HO2S (Sensor 2) 4P connector terminals No. 3 and No. 4 individually.

Fig 2: Checking Continuity Between Body Ground And Secondary HO2S (Sensor 2) 4P Connector Terminals No. 3 And No. 4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 22.

NO -Go to step 11.
Turn the ignition switch to ON (II).
Measure the voltage between secondary HO2S (Sensor 2) 4P connector terminals No. 3 and No. 4.

Fig 3: Measuring Voltage Between Secondary HO2S (Sensor 2) 4P Connector Terminals No. 3 And No. 4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 13.

NO -Go to step 17.
Turn the ignition switch to LOCK (0).
Jump the SCS line with the HDS.
Disconnect ECM/PCM connector C (44P).
Check for continuity between ECM/PCM connector terminal C28 and body ground.

Fig 4: Checking Continuity Between ECM/PCM Connector Terminal C28 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair a short in the wire between the ECM/PCM (C28) and secondary HO2S (Sensor 2), then go to step 23.

NO -Go to step 29.
Measure the voltage between secondary HO2S (Sensor 2) 4P connector terminal No. 4 and body ground.

Fig 5: Measuring Voltage Between Secondary HO2S (Sensor 2) 4P Connector Terminal No. 4 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 18.

NO -Repair an open in the wire between secondary HO2S (Sensor 2) and the No. B12 IMA (10 A) fuse, then go to step 23.
Turn the ignition switch to LOCK (0).
Jump the SCS line with the HDS.
Disconnect ECM/PCM connector C (44P).
Check for continuity between ECM/PCM connector terminal C28 and secondary HO2S (Sensor 2) 4P connector terminal No. 3.

Fig 6: Checking Continuity Between ECM/PCM Connector Terminal C28 And Secondary HO2S (Sensor 2) 4P Connector Terminal No. 3
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 29.

NO -Repair an open in the wire between the ECM/PCM (C28) and secondary HO2S (Sensor 2), then go to step 23.
Replace secondary HO2S (Sensor 2) (see SECONDARY HO2S REPLACEMENT ).
Reconnect all connectors.
Turn the ignition switch to ON (II).
Reset the ECM/PCM with the HDS.
Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0141 indicated?

YES -Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the ECM/PCM, then go to step 1.

NO -Go to step 28.
Monitor the OBD STATUS for DTC P0141 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?

YES -Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step 27, go to the indicated DTC'S TROUBLESHOOTING .

NO -If the HDS indicates FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the ECM/PCM, then go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.
Reconnect all connectors.
Update the ECM/PCM if it does not have the latest software (see ECM/PCM UPDATE ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ).
Start the engine, and let it idle.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0141 indicated?

YES -Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then go to step 31. If the ECM/PCM was substituted, go to step 1.

NO -Go to step 33.
Monitor the OBD STATUS for DTC P0141 in the DTCs MENU with the HDS.
Does the HDS indicate PASSED?

YES -If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ). If any other Pending or Confirmed DTCs were indicated in step 32, go to the indicated DTC'S TROUBLESHOOTING .

NO -If the HDS indicates FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then go to step 31. If the ECM/PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.