DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P2238

DTC P2238 : A/F Sensor (Sensor 1) AFS+ Circuit Low Voltage

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How to Troubleshoot the Fuel And Emissions Systems.


1. Problem verification:

-1. Turn the ignition switch to ON (II).

-2. Clear the DTC with the HDS. How to Troubleshoot the Fuel And Emissions Systems

-3. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P2238 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), the PGM-FI subrelay, and the PCM.

2. Shorted wire check (AFS+ line):

-1. Turn the ignition switch to LOCK (0).

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connectors






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










Is there continuity?
-YES- Repair a short in the AFS+ wire between the PCM (C39) and the A/F sensor (Sensor 1), then do the repair verification.
-NO- The AFS+ wire is OK. Go to step 3.

3. PCM internal circuit check:

-1. Reconnect PCM connector C (49P).

-2. Turn the ignition switch to ON (II).

-3. Measure the voltage between test points 1 and 2.










Is the voltage about 2.2 V?
-YES- The PCM internal circuit is OK. Replace the A/F sensor (Sensor 1) A/F Sensor Removal And Installation, then do the repair verification.
-NO- Update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then do the repair verification.

Repair verification:

-1. Turn the ignition switch to LOCK (0).

-2. Reconnect all connectors.

-3. Turn the ignition switch to ON (II).

-4. Reset the PCM with the HDS How to Troubleshoot the Fuel And Emissions Systems.

-5. Do the PCM idle learn procedure PCM Idle Learn Procedure.

-6. Monitor the OBD STATUS for DTC P2238 in the DTCs MENU with the HDS.






Does the HDS indicate PASSED, FAILED, or NOT COMPLETED?
-PASSED- Troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.
-FAILED- Go to step 1 and recheck. If the PCM was updated, substitute a known-good PCM Service and Repair, then check the OBD STATUS again.
-NOT COMPLETED - Keep idling until a result comes on.