DTC P0141, P0161: Rear Secondary HO2S (Bank 1, Sensor 2) Heater Circuit Malfunction (2006 Model); Front Secondary HO2S (Bank 2, Sensor 2) Heater Circuit Malfunction (2006 Model)

NOTE:

Information marked with an asterisk (*) applies to the front bank (Bank 2).
Before you troubleshoot, record all freeze data and any on-board snapshot, and review the GENERAL TROUBLESHOOTING INFORMATION .

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 and/or P0161* indicated?
1. YES - Go to step 5.
2. NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the ECM/PCM.
Turn the ignition switch OFF.
Check these fuses:
- No. 19 Fl ECU (ECM/PCM) (40 A) fuse in the under-hood fuse/relay box.
- No. 4 LAF (A/F SENSOR) (15 A) fuse in the under-dash fuse/relay box.
- No. 23 IGP (7.5 A) fuse in the under-dash fuse/relay box.
Are any of the fuses blown?
1. YES - Repair short in the wire between the A/F sensors, the secondary HO2S, the A/F sensor relay (LAF), and the fuses, then replace the blown fuse(s), and go to step 22.
2. NO - Go to step 7.
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.

Fig 1: Measuring Resistance Between Secondary HO2S (Sensor 2) 4P Connector Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there 5.4-6.6 Ω at room temperature?
1. YES - Go to step 9.
2. NO - Go to step 21.
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 & Secondary HO2S (Sensor 2) 4P Connector Terminals
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 21.
2. NO - Go to step 10.
Jump the SCS line with the HDS.
Disconnect ECM/PCM connector A (31P).
Check for continuity between ECM/PCM connector terminal A9 (A8)* and body ground.

Fig 3: Checking Continuity Between ECM/PCM Connector Terminal A9 (A8)* & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Repair short in the wire between the ECM/PCM (A9 (A8)*) and the secondary HO2S (Sensor 2), then go to step 22.
2. NO - Go to step 13.
Connect secondary HO2S (Sensor 2) 4P connector terminal No. 3 to body ground with a jumper wire.

Fig 4: Connecting Secondary HO2S (Sensor 2) 4P Connector Terminal No. 3 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between ECM/PCM connector terminal A9 (A8)* and body ground.

Fig 5: Checking Continuity Between ECM/PCM Connector Terminal A9 (A8)* & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 15.
2. NO - Repair open in the wire between the ECM/PCM (A9 (A8)*) and the secondary HO2S (Sensor 2), then go to step 22.
Connect secondary HO2S (Sensor 2) 4P connector terminal No. 4 to body ground with a jumper wire.

Fig 6: Connecting Secondary HO2S (Sensor 2) 4P Connector Terminal No. 4 To Body Ground With Jumper Wire
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Remove the A/F sensor relay (LAF) (A).

Fig 7: Removing A/F Sensor Relay (LAF)
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Check for continuity between A/F sensor relay (LAF) 4P connector terminal No. 2 and body ground.

Fig 8: Checking Continuity Between A/F Sensor Relay (LAF) 4P Connector Terminal No. 2 & Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 18.
2. NO - Repair open in the wire between the A/F sensor, the secondary HO2S, and the A/F sensor relay (LAF), then go to step 22.
Disconnect ECM/PCM connector E (31P).
Check for continuity between ECM/PCM connector terminal E4 and A/F sensor relay (LAF) 4P connector terminal No. 4.

Fig 9: Checking Continuity Between ECM/PCM Connector Terminal E4 & A/F Sensor Relay (LAF) 4P Connector Terminal No. 4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES - Go to step 20.
2. NO - Repair open in the wire between the ECM/PCM (E4) and the A/F sensor relay (LAF), then go to step 22.
Test the A/F sensor relay (LAF) (see POWER RELAY TEST ).
Is the A/F sensor relay (LAF) OK?
1. YES - Go to step 27.
2. NO - Replace the A/F sensor relay (LAF), then go to step 22.
Replace the secondary HO2S (Sensor 2) (see SECONDARY HO2S REPLACEMENT ).
Turn the ignition switch ON (II).
Reset the ECM/PCM with the HDS.
Do the ECM/PCM IDLE LEARN PROCEDURE .
Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
1. YES - If DTC P0141 and/or P0161* is indicated, check for poor connections or loose terminals at the secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the ECM/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.
2. NO - Go to step 26.
Monitor the OBD STATUS for DTC P0141 and/or P0161* in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
1. YES - Troubleshooting is complete.
2. NO - If the screen indicates FAILED, check for poor connections or loose terminals at the secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the ECM/PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 24. and recheck.
Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM (see HOW TO TROUBLESHOOT CIRCUITS AT THE ECM/PCM ).
Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
1. YES - If DTC P0141 and/or P0161* is indicated, check for poor connections or loose terminals at the secondary HO2S (Sensor 2), the A/F sensor relay (LAF), and the ECM/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.
2. NO - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).