Q: Malfunction indicator lamp is on!

Hi there:

Well, the dealership is partially correct here. The P2647 OBD-II trouble code indicates that the powertrain control module has detected a malfunction in the intake camshaft rocker arm actuator system (A). This code is usually found in vehicles that have variable valve timing; like your 2007 Honda Accord. Repairs that can resolve the issues that are caused by this trouble code would include, adding or changing the engine oil, replacing the timing belt or chain as well as other timing components, replacing the oil control valve or other variable valve timing components, repairing or replacing wiring or connectors that are associated with the variable valve timing system or in extreme cases; replacing the powertrain control module. If you’d like a second opinion about what needs to be replaced, you can have one of our professional mechanics complete a check engine light inspection; and determine if the oil pressure switch is the faulty component that needs to be replaced.

Code P2647 stands for Rocker Arm Oil Pressure Switch Circuit High Voltage. This switch is part of the the variable valve timing (VETC) system. The powertrain control module (PCM) activates an oil control solenoid to charge/discharge the hydraulic circuit of the VTEC mechanism that adjusts the valve timing. Obviously, this system is dependent on oil pressure, which is why there is an oil pressure switch downstream of the oil control solenoid to keep the PCM apprised of system operation. If the PCM senses a difference in requested and actual oil pressure, it will turn on the check engine light and set code P2647. The problem could be the switch, but then again, it could be any part of this system. Even a low oil level can trigger this code. A problem in this system can also cause the engine performance problems you are having. I recommend having the experts at YourMechanic properly diagnose this issue for you (https://www.yourmechanic.com/services/check-engine-light-is-on-inspection).