DTC Advanced Diagnostics: P2647
DTC P2647: Rocker Arm Pressure System Stuck On
General Description
| Logic Decision | Rocker Arm Oil Pressure Sensor | |
|---|---|---|
| 'High' | 'Low' | |
| Rocker Arm Oil Control Solenoid Command 'OFF' | Failure | Normal |
| Rocker Arm Oil Control Solenoid Command 'ON' | Normal | Failure |
The VTEC system activates the rocker arm oil control solenoid with a command from the powertrain control module (PCM), and it charges/discharges the hydraulic circuit of the VTEC mechanism that delays valve timing. The PCM monitors oil pressure in the hydraulic circuit of the VTEC mechanism using the rocker arm oil pressure sensor downstream of the rocker arm oil control solenoid. If there is a difference between the oil pressure condition in the hydraulic circuit determined by the PCM command and the oil pressure condition determined by the status of the rocker arm oil pressure sensor, the system is considered faulty, and a DTC is stored.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Once per driving cycle |
| Sequence | None |
| Duration | 2.5 seconds or more |
| DTC Type | Two drive cycles, MIL on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| 12 volt battery voltage [Battery] | 10.5 V | - |
| Other | At idle | |
[ ]: HDS Parameter
Malfunction Threshold
When the rocker arm oil control solenoid is OFF, the rocker arm oil pressure sensor output remains high (49 kPa (0.50 kgf/cm 2, 7.1 psi) or more).
Possible Cause
The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- Rocker arm oil control solenoid failure
- Rocker arm oil control solenoid VTS line open
- Rocker arm oil control solenoid VTS line short
- Rocker arm oil pressure sensor failure
- Rocker arm oil pressure sensor POIL line open
- Rocker arm oil pressure sensor POIL line short
- Oil passage clogged
Confirmation Procedure
Operating Condition
Start the engine, and let it idle for at least 3 seconds.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC, the freeze data, and the on-board snapshot are stored.
Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, the freeze data, and the on-board snapshot can be cleared with the scan tool clear command.