Circuit Description

The DTC P2647 Rocker Arm Actuator System Stuck On diagnostic monitors the operation of the rocker arm oil control solenoid. The rocker arm oil control solenoid enables the powertrain control module (PCM) to operate the high speed cam system. The high speed cam system significantly increases valve lift at engine speeds above 6,000 RPM. A second camshaft lobe with a high lift profile is cast into each camshaft, alongside the low/medium speed lobes. Unique rocker arms follow both the high speed and low/medium speed cam lobes. At engine speeds below 6,000 RPM, the low/medium speed cam lobes operate the rocker arms. When the rocker arm oil control solenoid is turned ON between 6,000-8,200 RPM, the rocker arms are operated by the high speed cam lobes. The rocker arm oil control solenoid is controlled by a pulse width modulated (PWM) signal from the PCM.

The rocker arm oil pressure switch detects oil pressure when oil is flowing through the rocker arm oil supply system. When the rocker arm oil control solenoid is ON, the oil pressure switch opens and the signal circuit to the PCM goes high. A DTC P2647 sets when the signal circuit of the rocker arm oil pressure switch is high when engine speed is less than 6,000 RPM. For additional information on the operation of the rocker arm oil control system, refer to Rocker Arm Oil Control System Description .