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.

DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P2648 Rocker Arm Oil Control Solenoid A (Bank 1) Circuit Low Voltage
      

1.
Problem verification:

Problem verification
?1.
Press the engine start/stop button to select the ON mode.

?2.
Clear the DTC with the HDS.


?3.
Select the VTEC+VCM TEST in the INSPECTION MENU, then select the SOLENOID B of the SOL.V.ACTIVATION with the HDS.

  

?4.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P2648 Rocker Arm Oil Control Solenoid A (Bank 1) Circuit Low Voltage
      

Is DTC P2648 indicated?

     
YES
     
     
     
The failure is duplicated. Go to step 2.
     
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.?
2.
Rocker arm oil control solenoid A (Bank 1) internal resistance check:

Rocker arm oil control solenoid A (Bank 1) internal resistance check
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Disconnect the following connector.

?3.
At the rocker arm oil control solenoid side, measure the resistance between test points 1 and 2.
Test condition
OFF mode
 
Rocker arm oil control solenoid A (Bank 1) 2P connector: disconnected
Test circuit
VTSB1, PG
Test point 1
Rocker arm oil control solenoid A (Bank 1) 2P connector No. 1 (rocker arm oil control solenoid side)
Test point 2
Rocker arm oil control solenoid A (Bank 1) 2P connector No. 2 (rocker arm oil control solenoid side)


Is there 14?30 ? at room temperature?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
3.
Shorted wire check (VTSB1 line):

Shorted wire check (VTSB1 B line)
?1.
Jump the SCS line with the HDS.


?2.
Disconnect the following connector.

?3.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
 
Rocker arm oil control solenoid A (Bank 1) 2P connector: disconnected
 
PCM connector C (51P): disconnected
Test circuit
VTSB1
Test point 1
PCM connector C (51P) No. 15 (LT GRN)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short in the VTSB1 wire between rocker arm oil control solenoid A (Bank 1) and the PCM (C15), then do the repair verification.
     
NO
     
     
     
The VTSB1 wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM, then do the repair verification.
Repair verification:

?1.
Reconnect all connectors.

?2.
Exit the SCS mode with the HDS.


?3.
Press the engine start/stop button to select the ON mode.

?4.
Reset the PCM with the HDS.


?5.
Do the PCM idle learn procedure.

?6.
Select the VTEC+VCM TEST in the INSPECTION MENU, then select the SOLENOID B of the SOL.V.ACTIVATION with the HDS.

  

?7.
Check for Pending or Confirmed DTCs with the HDS.
DTC Description
Confirmed DTC
Pending DTC
Freeze Frame
P2648 Rocker Arm Oil Control Solenoid A (Bank 1) Circuit Low Voltage
      


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, then recheck. If the PCM was substituted, go to step 1.
     
NO
     
     
     
Troubleshooting is complete. If the PCM was substituted, replace the original PCM. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.?