With A/T

DTC Troubleshooting: P2648

DTC P2648: Rocker Arm Oil Control Solenoid A (Bank 1) 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. Select the VTEC TEST in the INSPECTION MENU with the HDS, and do the Solenoid Valve ACTIVATION of the ROCKER ARM OIL CONTROL SOL A (B1).

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

Is DTC P2648 indicated?
YES - Go to step 5.

NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at rocker arm oil control solenoid A (Bank 1) and the PCM.


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

6. Disconnect the rocker arm oil control solenoid A (Bank 1) 2P connector.

7. Measure the resistance between rocker arm oil control solenoid A (Bank 1) 2P connector terminals No. 1 and No. 2.

Is there 13.6-16.9 Ohms at room temperature?
YES - Go to step 8.

NO - Go to step 11.






8. Jump the SCS line with the HDS.

9. Disconnect PCM connector B (49P).

10. Check for continuity between PCM connector terminal B49 and body ground.

Is there continuity?
YES - Repair short in the wire between the PCM (B49) and rocker arm oil control solenoid A (Bank 1), then go to step 12.

NO - Check for poor connections or loose terminals at PCM and rocker arm oil control solenoid A (Bank 1), then go to step 19.






11. Replace the rear rocker arm oil control valve. Rear Rocker Arm Oil Control Valve Replacement (J35Z2 Engine)

12. Reconnect all connectors.

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

14. Reset the PCM with the HDS.

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

16. Select the VTEC TEST in the INSPECTION MENU with the HDS, and do the Solenoid Valve ACTIVATION of the ROCKER ARM OIL CONTROL SOL A (B1).

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

Is DTC P2648 indicated?
YES - Check for poor connections or loose terminals at rocker arm oil control solenoid A (Bank 1) and the PCM, then go to step 1.

NO - Go to step 18.


18. 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 Temporary DTCs or DTCs were indicated in step 17, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, go to step 1 and recheck. If the screen indicates NOT COMPLETED, go to step 16.


19. Reconnect all connectors.

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

21. Select the VTEC TEST in the INSPECTION MENU with the HDS, and do the Solenoid Valve ACTIVATION of the ROCKER ARM OIL CONTROL SOL A (B1).

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

Is DTC P2648 indicated?
YES - Check for poor connections or loose terminals at rocker arm oil control solenoid A (Bank 1) and the PCM. If the PCM was updated, substitute a known-good PCM, Initial Inspection and Diagnostic Overview then go to step 21. If the PCM was substituted, go to step 1.

NO - Go to step 23.


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

Does the screen indicate PASSED?
YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. Service and Repair If any other Temporary DTCs or DTCs were indicated in step 22, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at rocker arm oil control solenoid A (Bank 1) and the PCM. If the PCM was updated, substitute a known-good PCM, Initial Inspection and Diagnostic Overview then go to step 21. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, go to step 21.