DTC P0138 (KA/Kc) (2016 2017 2018 2019)

DTC P0138  : Secondary HO2S (Sensor 2) Circuit High Voltage

NOTE:  Before you troubleshoot, review the general troubleshooting information .

DTC (PGM-FI)

1. Problem verification

   -1. Turn the vehicle to the ON mode.

   -2. Clear the DTC with the HDS.

   -3. Start the engine.

   -4. Hold the engine speed at 3, 000 rpm without load (CVT in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.

   Signal	Current conditions
   	Values	Unit
   ECT SENSOR 1
   ENGINE SPEED

   -5. Check the parameter (s) below with the HDS.

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   HO2S S2	More than 1.27	V

   Do the current condition (s) match the threshold?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and the PCM. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot .

2. Determine possible failure area (secondary HO2S (Sensor 2), others)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connector.

   Secondary HO2S (Sensor 2) 4P connector

   -3. Connect terminals A and B with a jumper wire.

   Terminal A	Secondary HO2S (Sensor 2) 4P connector No. 1
   Terminal B	Secondary HO2S (Sensor 2) 4P connector No. 2

   Courtesy of HONDA, U.S.A., INC.

   -4. Turn the vehicle to the ON mode.

   -5. Check the parameter (s) below with the HDS.

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   HO2S S2	More than 1.27	V

   Do the current condition (s) match the threshold?

   YES 

   Go to step 3.

   NO 

   Replace secondary HO2S (Sensor 2) .

3. Open wire check (SO2SG/SO2 SG line)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Remove the jumper wire from the secondary HO2S (Sensor 2) 4P connector.

   -3. Connect terminals A and B with a jumper wire.

   Terminal A

   Secondary HO2S (Sensor 2) 4P connector No. 1

   Terminal B

   Body ground

   Courtesy of HONDA, U.S.A., INC.

   -4. Turn the vehicle to the ON mode.

   -5. Check the parameter (s) below with the HDS.

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   HO2S S2	More than 1.27	V

   Do the current condition (s) match the threshold?

   YES 

   The SO2SG/SO2 SG wire is OK. Go to step 4.

   NO 

   Repair an open in the SO2SG/SO2 SG wire between the PCM (B40) and secondary HO2S (Sensor 2).

4. Open wire check (SO2 line)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Jump the SCS line with the HDS.

   -3. Disconnect the following connector.

   PCM connector B (51P)

   -4. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	Secondary HO2S (Sensor 2) 4P connector: disconnected
   	Secondary HO2S (Sensor 2) 4P connector No. 1: jumped to body ground
   	PCM connector B (51P): disconnected
   Test point 1	PCM connector B (51P) No. 17
   Test point 2	Body ground

   Is there continuity?

   YES 

   The SO2 wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM , then recheck. If DTC P0138 goes away and the PCM was updated, troubleshooting is complete. If DTC P0138 goes away and the PCM was substituted, replace the original PCM .

   NO 

   Repair an open in the SO2 wire between the PCM (B17) and secondary HO2S (Sensor 2).