P2646 HONDA - Rocker Arm Oil Pressure Switch Circuit Low Voltage
- Faulty Variable Valve Timing and Lift Electronic Control (VTEC) / Rocker Arm Oil Pressure Switch
- VTEC/Rocker Arm Oil Pressure Switch harness is open or shorted
- VTEC/Rocker Arm Oil Pressure Switch circuit poor electrical connection
There is a Factory Service Bulletin for the following Honda Models
2003-2012 Honda Accord L4
2002-2005 Honda Civic Si
2002-2009 Honda CR-V
2011 Honda CR-Z
2003-2011 Honda Element
2007-2011 Honda Fit
The factory bulletin suggest that replacing the VTEC oil pressure switch (P/N 37250-PNE-G01, H/C 6737217) take care of the problem.
The Variable Valve Timing and Lift Electronic Control (VTEC) system activates the Rocker Arm Oil Control Solenoid (VTEC Solenoid Valve) by command from the Engine Control Module (ECM) / Powertrain Control Module (PCM), and it charges/discharges the hydraulic circuit of the VTEC mechanism that switches valve timing between Low and High. The ECM/PCM monitors oil pressure in the hydraulic circuit of the VTEC mechanism using the rocker arm oil pressure switch (VTEC oil pressure switch) downstream of the rocker arm oil control solenoid (VTEC solenoid valve). If there is a difference between the oil pressure condition in the hydraulic circuit that is determined by the ECM/PCM command and the oil pressure condition that is determined by the status of the rocker arm oil pressure switch (VTEC oil pressure switch), the system is considered faulty, and the Diagnostic Trouble Code (DTC) is stored.