DTC P2237, P2240

DTC P2237  : Rear A/F Sensor (Bank 1, Sensor 1) IP Circuit High Voltage DTC P2240  : Front A/F Sensor (Bank 2, Sensor 1) IP Circuit High 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 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), or How to Troubleshoot the A/T System (2014 2015) .
• 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. Check for Pending or Confirmed DTCs with the HDS.

   DTC Description	Confirmed DTC	Pending DTC	Freeze Frame
   P2237 Rear A/F Sensor (Bank 1, Sensor 1) IP Circuit High Voltage
   P2240 Front A/F Sensor (Bank 2, Sensor 1) IP Circuit High Voltage

   Is DTC P2237 and/or P2240 * indicated?

   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 the A/F sensor (Sensor 1) 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. Open wire check (IPB1 line (IPB2 line)*)

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

   - 2. Jump the SCS line with the HDS.

   - 3. Disconnect the following connectors.

   PCM connector C (51P) - Refer to: How to Troubleshoot the Fuel and Emissions Systems, 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), or How to Troubleshoot the A/T System (2014 2015)

   A/F sensor (Sensor 1) 6P connector

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

   Test condition	Vehicle OFF (LOCK) mode
   	PCM connector C (51P): disconnected
   	A/F sensor (Sensor 1) 6P connector: disconnected
   Test circuit	IPB1 (IPB2) *
   Test point 1	Rear A/F sensor (Bank 1, Sensor 1) 6P connector No. 5 (GRN)
   	Front A/F sensor (Bank 2, Sensor 1) 6P connector No. 5 (PUR) *
   Test point 2	PCM connector C (51P) No. 37 (GRN)
   	PCM connector C (51P) No. 38 (PUR) *

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

   Is there continuity?

   YES 

   The IPB1 (IPB2) * wire is OK. Go to step 3.

   NO 

   Repair an open in the IPB1 (IPB2) * wire between the PCM (C37 (C38) *) and the A/F sensor (Sensor 1).

3. PCM internal circuit check

   -1. Reconnect the following connector.

   PCM connector C (51P) - Refer to: How to Troubleshoot the Fuel and Emissions Systems, 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), or How to Troubleshoot the A/T System (2014 2015)

   - 2. Exit the SCS mode 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. Measure the voltage between test points 1 and 2.

   Test condition	Engine running
   	A/F sensor (Sensor 1) 6P connector: disconnected
   Test circuit	IPB1 (IPB2) *
   Test point 1	Rear A/F sensor (Bank 1, Sensor 1) 6P connector No. 5 (GRN)
   	Front A/F sensor (Bank 2, Sensor 1) 6P connector No. 5 (PUR) *
   Test point 2	Body ground

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

   Is there about 0.2 V or less?

   YES 

   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) .

   NO 

   The PCM internal circuit is OK. Replace the A/F sensor (Sensor 1) .