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 Pending or Confirmed 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 12.

NO -

Go to step 9.

9. Reconnect ECM connector C (44P).

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

11. Measure the voltage between A/F sensor (Sensor 1) 4P connector terminal No. 2 and body ground.





Is the voltage about 2.2 V?

YES -

Replace the A/F sensor (Sensor 1) A/F Sensor Replacement, then go to step 12.

NO -

Reconnect the A/F sensor (Sensor 1) 4P connector, then go to step 18.

12. Reconnect all connectors.

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

14. Reset the ECM with the HDS.

15. Do the ECM idle learn procedure ECM/PCM Idle Learn Procedure.

16. Check for Pending or Confirmed 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 18.

NO -

Go to step 17.

17. 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 Pending or Confirmed DTCs were indicated in step 16, 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.

18. Update the ECM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM.

19. Start the engine, and let it idle.

20. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P2238 indicated?

YES -

If the ECM was updated, substitute a known-good ECM, then go to step 19. If the ECM was substituted, go to step 1.

NO -

Go to step 21.

21. 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 Pending or Confirmed DTCs were indicated in step 20, 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, then go to step 19. If the ECM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.