P2647

DTC P2647

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.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P2647 Rocker Arm Actuator System Stuck On

CONDITIONS FOR RUNNING THE DTC
- DTCs P0100, P0101, P0102, P0103, P0115, P0117, P0118, P0125, P0335, P0340, P0341, P0385 are not set.
- The engine has been running at least 10 seconds.
- Engine speed is more than 6,000 RPM.
- The engine coolant temperature (ECT) is at least 60°C (140°F).
- The vehicle is operating at more than 10 km/h (6 mph).
- DTC P2647 runs continuously when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
- The signal circuit of the rocker arm oil pressure switch stays high.
- The above condition is present for at least 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The PCM illuminates the malfunction indicator lamp (MIL).
- The PCM stores the conditions that were present when the DTC set as Freeze Frame data.

CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
- A DTC clears after 40 consecutive warm-up cycles have occurred without a fault.
- A DTC can be cleared by using the scan tool Clear DTC Information function.

TEST DESCRIPTION

Steps 1 - 10:

Steps 11 - 16:

The numbers below refer to the step numbers on the diagnostic table.
1. The Diagnostic System Check - Vehicle prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool, if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
2. This step checks whether the rocker arm oil control solenoid is stuck ON. When ON at idle or low engine speed, the solenoid increases valve lift enough to cause the engine to run rough or stall.
7. The rocker arm oil pressure switch is closed when oil pressure is less than 20 kPa (3 psi).
9. This step visually inspects the operation of the rocker arm oil control solenoid. The solenoid plunger and spool valve movement should be smooth and rapid from extended to retracted positions.