DTC P0137, P0157

DTC P0137  : Rear Secondary HO2S (Bank 1, Sensor 2) Circuit Low Voltage DTC P0157  : Front Secondary HO2S (Bank 2, Sensor 2) Circuit Low Voltage

NOTE: 

• Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions Systems,  or How to Troubleshoot the A/T System (2014 2015),  or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016) .
• Information marked with an asterisk (*) applies to the front bank (Bank 2).

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. Hold the engine speed at 3, 000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.

   - 4. Monitor the OBD STATUS for DTC P0137 and/or P0157 * in the DTCs MENU with the HDS.

   DTC Description	OBD STATUS
   P0137 Rear Secondary HO2S (Bank 1, Sensor 2) Circuit Low Voltage
   P0157 Front Secondary HO2S (Bank 2, Sensor 2) Circuit Low Voltage

   Does the HDS indicate FAILED?

   YES 

   The failure is duplicated. Go to step 2.

   NO 

   If the HDS indicates PASSED, 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 HDS indicates EXECUTING, keep idling until a result comes on. If the HDS indicates OUT OF CONDITION, go to step 1-3 and recheck.

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. Turn the vehicle to the ON mode.

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

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   HO2S B1 S2	Less than 0.12	V
   HO2S B2 S2	Less than 0.12	V

   Do the current condition(s) match the threshold?

   YES 

   Go to step 3.

   NO 

   Replace secondary HO2S (Sensor 2) .

3. Determine possible failure area (SO2B1 (SO2B2)* line, SO2SGB1 (SO2SGB2)* line, others)

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

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

   Test condition	Vehicle OFF (LOCK) mode
   	Front and rear secondary HO2S (Sensor 2) 4P connectors: disconnected
   	Front and rear A/F sensor (Sensor 1) 6P connectors: disconnected

   Test circuit	SO2B1 (SO2B2) *
   Test point 1	Secondary HO2S (Sensor 2) 4P connector No. 2 (GRN)
   	Secondary HO2S (Sensor 2) 4P connector No. 1 (BLU) *
   Test point 2	Body ground

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

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

   Is there continuity?

   YES 

   Go to step 4.

   NO 

   Go to step 5.

4. Shorted wire check (SO2B1 (SO2B2)* line)

   -1. Jump the SCS line with the HDS.

   - 2. Disconnect the following connector.

   PCM connector C (51P) - Refer to: How to Troubleshoot the Fuel and Emissions Systems,  or How to Troubleshoot the A/T System (2014 2015),  or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016)

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

   Test condition	Vehicle OFF (LOCK) mode
   	PCM connector C (51P): disconnected
   	Front and rear secondary HO2S (Sensor 2) 4P connectors: disconnected
   	Front and rear A/F sensor (Sensor 1) 6P connectors: disconnected
   Test circuit	SO2B1 (SO2B2) *
   Test point 1	Secondary HO2S (Sensor 2) 4P connector No. 2 (GRN)
   	Secondary HO2S (Sensor 2) 4P connector No. 1 (BLU) *
   Test point 2	Body ground

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

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

   Is there continuity?

   YES 

   Repair a short in the SO2B1 (SO2B2) * wire between the PCM (C30 (C31) *) and secondary HO2S (Sensor 2).

   NO 

   The SO2B1 (SO2B2) * wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM - Refer to: PCM Removal and Installation (2016), or PCM Removal and Installation (2014 2015) .

5. Shorted wire check (SO2SGB1 (SO2SGB2) * line):

   - 1.Jump the SCS line with the HDS.

   - 2. Disconnect the following connector.

   PCM connector C (51P) - Refer to: How to Troubleshoot the Fuel and Emissions Systems,  or How to Troubleshoot the A/T System (2014 2015),  or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016)

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

   Test condition	Vehicle OFF (LOCK) mode
   	PCM connector C (51P): disconnected
   	Front and rear secondary HO2S (Sensor 2) 4P connectors: disconnected
   	Front and rear A/F sensor (Sensor 1) 6P connectors: disconnected
   Test circuit	SO2SGB1 (SO2SGB2) *
   Test point 1	Secondary HO2S (Sensor 2) 4P connector No. 1 (WHT)
   	Secondary HO2S (Sensor 2) 4P connector No. 2 (YEL) *
   Test point 2	Body ground

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

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

   Is there continuity?

   YES 

   Repair a short in the SO2SGB1 (SO2SGB2) * wire between the PCM (C39 (C40) *) and secondary HO2S (Sensor 2).

   NO 

   The SO2SGB1 (SO2SGB2) * wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .