DTC P0134: Rear A/F Sensor (Bank 1, Sensor 1) Heater System Malfunction; DTC P0154: Front A/F Sensor (Bank 2, Sensor 1) Heater System Malfunction

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
If DTC P2251 and/or P2254* is stored at the same time as DTC P0134 and/or P0154*, troubleshoot DTC P2251 and/or P2254* first, then recheck for P0134 and/or P0154*.
Information marked with an asterisk (*) applies to the front bank (Bank 2).

Turn the ignition switch to ON (II).
Clear the DTC with the HDS.
Start the engine, and let it idle without load (in P or N) for at least 1 minute.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0134 and/or P0154* 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 A/F sensor (Sensor 1), the under-hood fuse/relay box (PGM-FI subrelay), and the PCM.
Turn the ignition switch to LOCK (0).
Jump the SCS line with the HDS.
Disconnect the A/F sensor (Sensor 1) 6P connector.
Disconnect PCM connector B (49P).
Check for continuity between A/F sensor (Sensor 1) 6P connector terminal No. 4 and PCM connector terminal B13(B14)*.

Fig 1: Checking Continuity Between A/F Sensor (Sensor 1) 6P Connector Terminal No. 4 And PCM Connector Terminal B13 (B14)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 10.

NO -Repair an open in the wire between the PCM (B13 (B14)*) and the A/F sensor (Sensor 1), then go to step 14.
Reconnect PCM connector B (49P).
Start the engine, and let it idle without load (in P or N) for at least 1 minute.
Measure the voltage between A/F sensor (Sensor 1) 6P connector terminal No. 4 and body ground.

Fig 2: Measuring Voltage Between A/F Sensor (Sensor 1) 6P Connector Terminal No. 4 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there about 0.2 V or less?

YES -Go to step 20.

NO -Go to step 13.
Replace the A/F sensor (Sensor 1) (see A/F SENSOR REPLACEMENT ).
Reconnect all connectors.
Turn the ignition switch to ON (II).
Reset the PCM with the HDS.
Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0134 and/or P0154* indicated?

YES -Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the under-hood fuse/relay box (PGM-FI subrelay), and the PCM, then go to step 1.

NO -Go to step 19.
Monitor the OBD STATUS for DTC P0134 and/or P0154* 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 18, go to the indicated DTC'S TROUBLESHOOTING .

NO -If the HDS indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the under-hood fuse/relay box (PGM-FI subrelay), and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.
Turn the ignition switch to LOCK (0).
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 without load (in P or N) for at least 1 minute.
Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0134 and/or P0154* indicated?

YES -Check for poor connections or loose terminals at the A/F sensor (Sensor 1), the under-hood fuse/relay box (PGM-FI subrelay), and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 23. If the PCM was substituted, go to step 1.

NO -Go to step 25.
Monitor the OBD STATUS for DTC P0134 and/or P0154* in the DTCs MENU with the HDS.
Does the HDS 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 Pending or Confirmed DTCs were indicated in step 24, go to the indicated DTC'S TROUBLESHOOTING .

NO -If the HDS indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1), the under-hood fuse/relay box (PGM-FI subrelay), and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 23. If the PCM was substituted, go to step 1. If the HDS indicates NOT COMPLETED, keep idling until a result comes on.