Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0141: Secondary HO2S (Sensor 2) Heater Circuit Malfunction
- Turn the ignition switch ON (II).
- Clear the DTC with the HDS.
- Start the engine.
- Check for Temporary DTCs or 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 the secondary HO2S (Sensor 2) and the PCM.
- Turn the ignition switch OFF.
- Check the No. 3 IG1 ACG (15A) fuse in the under-dash fuse/relay box.
Is the fuse OK?
YES - Go to step 7.
NO - Repair short in the wire between the secondary HO2S (Sensor 2) and the No. 3 IG1 ACG (15A) fuse. Also replace the No. 3 IG1 ACG (15A) fuse, then go to step 23.
- Disconnect the secondary HO2S (Sensor 2) 4P connector.
- At the secondary HO2S (Sensor 2) side, measure 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?
YES - Go to step 9.
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 4
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES - Go to step 22.
NO - Go to step 10.
- Turn the ignition switch ON (II).
- Measure 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 12.
NO - Go to step 16.
- Turn the ignition switch OFF.
- Jump the SCS line with the HDS.
- Disconnect PCM connector B (44P).
- Check for continuity between PCM connector terminal B4 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES - Repair short in the wire between the PCM (B4) and the secondary HO2S (Sensor 2), then go to step 23.
NO - Go to step 29.
- Measure voltage between secondary HO2S (Sensor 2) 4P connector terminal No. 3 and body ground.Fig 5: Measuring Voltage Between Secondary HO2S (Sensor 2) 4P Connector Terminal No. 3 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there battery voltage?
YES - Go to step 17.
NO - Repair open in the wire between the secondary HO2S (Sensor 2) and the No. 3 IG1 ACG (15A) fuse, then go to step 23.
- Turn the ignition switch OFF.
- Jump the SCS line with the HDS.
- Disconnect PCM connector B (44P).
- Connect secondary HO2S (Sensor 2) 4P connector terminal No. 4 to body ground with a jumper wire.
- Check for continuity between PCM connector terminal B4 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES - Go to step 29.
NO - Repair open in the wire between the PCM (B4) and the secondary HO2S (Sensor 2), then go to step 23.
- Replace the secondary HO2S (Sensor 2) (see A/F SENSOR REPLACEMENT ).
- Reconnect all connectors.
- Turn the ignition switch ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
- Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0141 indicated?
YES - Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the 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 screen indicate PASSED?
YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 27, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.
- Reconnect all connectors.
- Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
- Start the engine, and let it idle.
- Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0141 indicated?
YES - Check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 31. If the 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 screen indicate PASSED?
YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). If any other Temporary DTCs or DTCs were indicated in step 32, go to the indicated DTCs troubleshooting.
IMO-If the screen indicates FAILED, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 31. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.