VTEC System Stuck ON

DTC P2647: VTEC System Stuck ON (Engine Type: J35A7)




General Description
The variable cylinder management (VCM) system activates the rocker arm oil control solenoid by command from the powertrain control module (PCM), and it charges/discharges the hydraulic circuit of the cylinder pause VTEC system that pauses the intake and exhaust valves on the rear bank. The PCM monitors oil pressure in the hydraulic circuit of the VTEC mechanism using the engine oil pressure (EOP) sensor downstream of the rocker arm oil control solenoid. If there is a difference between the oil pressure condition in the hydraulic circuit that is determined by the PCM command and the oil pressure condition that is determined by the status of the EOP sensor, the system is considered faulty, and a DTC is stored.




Monitor Execution, Sequence, Duration, DTC Type, OBD Status




Enable Conditions

Malfunction Threshold
When the rocker arm oil control solenoid is ON, the EOP sensor output remains High (39 kPa (11.6 in.Hg, 293 mmHg) or more).

Confirmation Procedure with the HDS
Do the VTEC TEST in the INSPECTION MENU with the HDS.

Driving Pattern
1. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on.
2. Hold the engine speed between 1,500 rpm and 3,000 rpm with a MAP value of 27 kPa (200 mmHg, 7.9 in.Hg) for at least 5 seconds.

- Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

Diagnosis Details

Conditions for illuminating the MIL
When a malfunction is detected, the MIL comes on and the DTC and the freeze frame data are stored in the PCM memory.

Conditions for clearing the MIL
The MIL will be cleared if the malfunction does not recur during three consecutive trips in which the diagnostic runs.

The MIL, the DTC, and the freeze frame data can be cleared by using the scan tool Clear command or by disconnecting the battery.