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

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 3000 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.

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)

   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), then do the repair verification.

3. PCM internal circuit check

   -1. Reconnect the following connector.

   PCM connector C (51P)

   -2. Exit the SCS mode with the HDS.

   -3. Start the engine. Hold the engine speed at 3000 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 , then do the repair verification.

   NO 

   The PCM internal circuit is OK. Replace the A/F sensor (Sensor 1) , then do the repair verification.

4. Repair verification (OBD STATUS check)

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

   -2. Reconnect all connectors.

   -3. Exit the SCS mode with the HDS.

   -4. Turn the vehicle to the ON mode.

   -5. Reset the PCM with the HDS .

   Reset PCM

   -6. Do the PCM idle learn procedure.

   -7. Monitor the OBD STATUS for DTC P2237 and/or P2240 * in the DTCs MENU with the HDS.

   DTC Description	OBD STATUS
   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

   DTC (PGM-FI)

   Does the HDS indicate PASSED, FAILED, or NOT COMPLETED?

   PASSED (P2237)

   Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.

   PASSED (P2240)

   Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.

   FAILED (P2237)

   Go to step 1 and recheck.

   FAILED (P2240)

   Go to step 1 and recheck.

   NOT COMPLETED

   Keep idling until a result comes on.