DTC Troubleshooting

DTC Troubleshooting: P2648, P2648

DTC P2648:

Rocker Arm Oil Control Solenoid 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), or press the engine start/stop button to select the ON mode.

2. Clear the DTC with the HDS.

3. Do the VTEC TEST in the INSPECTION MENU with the HDS.

Is the result OK?

YES -

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the rocker arm oil control solenoid and the ECM/PCM.�

NO -

Go to step 4.

4. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

5. Disconnect the rocker arm oil control solenoid 1P connector.

6. At the solenoid side, measure the resistance between the rocker arm oil control solenoid 1P connector terminal and the solenoid valve body.





Is there 14-30 Ohms at room temperature?

YES -

Go to step 7.

NO -

Go to step 10.

7. Jump the SCS line with the HDS.

8. Disconnect ECM/PCM connector B (49P).

9. Check for continuity between ECM/PCM connector terminal B39 and body ground.





Is there continuity?

YES -

Repair short in the wire between the ECM/PCM(B39) and the rocker arm oil control solenoid, then go to step 11.

NO -

Go to step 18.

10. Replace the rocker arm oil control solenoid Service and Repair.

11. Reconnect all connectors.

12. Turn the ignition switch ON (II), or press the engine start/stop button to select the ON mode.

13. Reset the ECM/PCM with the HDS.

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

15. Do the VTEC TEST in the INSPECTION MENU with the HDS.

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

Is DTC P2648 indicated?

YES -

Check for poor connections or loose terminals at the rocker arm oil control solenoid and the ECM/PCM, then go to step 1.

NO -

Go to step 17.

17. Monitor the OBD STATUS for DTC P2648 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 rocker arm oil control solenoid and the ECM/PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 15.

18. Reconnect all connectors.

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

20. Do the VTEC TEST in the INSPECTION MENU with the HDS.

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

Is DTC P2648 indicated?

YES -

Check for poor connections or loose terminals at the rocker arm oil control solenoid and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to step 20. If the ECM/PCM was substituted, go to step 1.

NO -

Go to step 22.

22. Monitor the OBD STATUS for DTC P2648 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES -

If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair. If any other Pending or Confirmed DTCs were indicated in step 21, go to the indicated DTC's troubleshooting.�

NO -

If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil control solenoid and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to step 20. If the ECM/PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, go to step 20.