DTC P2237 Or DTC P2240

Code Definition

DTC P2237: Rear Air Fuel Ratio Sensor IP Line High Voltage (Bank 1, Sensor 1)
DTC P2240: Front Air Fuel Ratio Sensor IP Line High Voltage (Bank 2, Sensor 1)

CAUTION: When substituting or replacement of PCM is recommended, see PCM REMOVAL & REPLACEMENT for important precautions.

NOTE: This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

NOTE: If DTC P2237 and/or (P2240) is stored at the same time as DTC P0134 and/or (P0154), troubleshoot DTC P2237 and/or (P2240) first , then recheck for DTC P0134 and/or (P0154).

Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2237 and/or (P2240) are set, go to next step. If DTCs P2237 and/or (P2240) are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at Air Fuel Ratio sensor and PCM connectors.
Turn ignition off. Disconnect A/F ratio sensor 8-pin connector. See Figure . Disconnect PCM harness connector "A". See Figure . Go to next step.
With a fused jumper wire, connect A/F ratio sensor 8-pin connector terminal No. 7 to ground. Check continuity between ground and PCM harness connector terminals A55 (A51). If there is continuity, go to next step. If there is no continuity, repair open in wire between A/F ratio sensor 8-pin connector and PCM. Go to step 8 .
Remove the jumper wire from A/F ratio sensor connector and reconnect PCM harness connector "A". Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
Measure voltage between ground and A/F ratio sensor 8-pin connector terminal No. 7. If there is about 0.2 volt or less, go to step 12 . If there is not about 0.2 volt or less, go to next step.
Replace A/F ratio sensor.
Reconnect PCM harness connector "A" and A/F ratio sensor 8-pin connector. Turn ignition on. Go to next step.
Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See PCM IDLE LEARN PROCEDURE . Go to next step.
Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2237 and/or (P2240) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2237 and/or (P2240) are not set, go to next step.
Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P2237 and/or (P2240) in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1 . If it is NOT COMPLETED, go to step 10 and recheck.
Update the PCM if it does not have the latest software, or substitute a known-good PCM. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2237 and/or (P2240) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.