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:

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

-2. Clear the DTC with the HDS.

-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 ECM.

2. Shorted wire check (AFS+ line):

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 ECM (C39) and the A/F sensor (Sensor 1), then do the repair verification.
-NO- The AFS+ wire is OK. Go to step 3.

3. ECM internal circuit check:

ECM internal circuit check:
-1. Reconnect the ECM 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 ECM 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 ECM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM 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 ECM with the HDS How To Troubleshoot The Fuel And Emissions Systems.

-5. Do the ECM idle learn procedure ECM/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 ECM was substituted, replace the original ECM Service and Repair. Check for other DTC after this troubleshooting. 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 ECM was updated, substitute a known-good ECM Service and Repair, then check the OBD STATUS again.
-NOT COMPLETED - Keep idling until a result comes on.