DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: 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 How to Troubleshoot the Fuel And Emissions Systems.


1. Problem verification:

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

-2. Clear the DTC with the HDS. How to Troubleshoot the Fuel And Emissions Systems

-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 pressure switch, the rocker arm oil control solenoid, and the PCM.
-NO- The failure is duplicated. Go to step 2.

2. Rocker arm oil control solenoid internal resistance check:

-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.






-3. At the rocker arm oil control solenoid side, measure the resistance between test points 1 and 2.










Is there 14-30 Ohms at room temperature?
-YES- Go to step 3.
-NO- Replace the rocker arm oil control valve Rocker Arm Oil Control Valve Removal And Installation, then do the repair verification.

3. Shorted wire check (VT SOL line):

-1. Jump the SCS line with the HDS.

-2. Disconnect the following connector.






-3. Check for continuity between test points 1 and 2.










Is there continuity?
-YES- Repair a short in the VT SOL wire between the rocker arm oil control solenoid and the PCM (B33), then do the repair verification.
-NO- The VT SOL wire is OK. Update the PCM PCM Update if it does not have the latest software, or substitute a known-good PCM Service and Repair, then do the repair verification.

Repair verification:

-1. Reconnect all connectors.

-2. Turn the ignition switch to ON (II).

-3. Reset the PCM with the HDS How to Troubleshoot the Fuel And Emissions Systems.

-4. Do the PCM idle learn procedure PCM Idle Learn Procedure.

-5. Do the VTEC TEST in the INSPECTION MENU with the HDS.

-6. 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 pressure switch, the rocker arm oil control solenoid, and the PCM. If the PCM was updated, substitute a known-good PCM Service and Repair, then recheck. If the PCM was substituted, go to step 1.
-NO- Troubleshooting is complete. If the PCM was substituted, replace the original PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.