DTC Troubleshooting

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. Initial Inspection and Diagnostic Overview

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

2. Clear the DTC with the HDS.

3. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P2238 indicated?
YES - Go to step 4.

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 ECM.


4. Turn the ignition switch to LOCK (0).

5. Jump the SCS line with the HDS.

6. Disconnect the A/F sensor (Sensor 1) 4P connector.

7. Disconnect ECM connector C (44P).

8. Check for continuity between ECM connector terminal C29 and body ground.

Is there continuity?
YES - Repair short in the wire between the ECM (C29) and the A/F sensor (Sensor 1), then go to step 10.

NO - Go to step 9.






9. Replace the A/F sensor (Sensor 1). A/F Sensor Replacement

10. Reconnect all connectors.

11. Turn the ignition switch to ON (II).

12. Reset the ECM with the HDS.

13. Do the ECM idle learn procedure. ECM Idle Learn Procedure

14. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P2238 indicated?
YES - Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the ECM, then go to step 1. If the connections and the terminals are OK, go to step 16.

NO - Go to step 15.


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

Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 14, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the ECM, then go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.


16. Update the ECM if it does not have the latest software, ECM Update or substitute a known-good ECM. Initial Inspection and Diagnostic Overview

17. Start the engine, and let it idle.

18. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P2238 indicated?
YES - If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 17. If the ECM was substituted, go to step 1.

NO - Go to step 19.


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

Does the screen indicate PASSED?
YES - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. Service and Repair If any other Temporary DTCs or DTCs were indicated in step 18, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, go to step 1. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 17. If the ECM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.