DTC Advanced Diagnostics: P2651 (2.0L Engine) (2024 2025)
DTC P2651 : Rocker Arm Oil Pressure Switch Performance/Stuck off
General Description
The powertrain control module (PCM) controls the switching of the exhaust valve timing by actuating the rocker arm oil control solenoid. The PCM monitors oil pressure in the hydraulic circuit of the VTEC mechanism using the rocker arm oil pressure switch. If the switching is active despite there is no feedback from rocker arm oil pressure switch, the PCM detects a malfunction and stores a DTC.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 5 seconds or more |
| DTC Type | One drive cycle, MIL on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time after starting the engine | 5 seconds | - |
| Engine coolant temperature [ECT Sensor 1] | -238.07 deg.F (-150.04 deg.C) | 302.1 deg.F (150.06 deg.C) |
| Engine oil temperature [Engine Oil Temperature] | 49.93 deg.F (9.96 deg.C) | 5, 438.4 deg.F (3, 003.56 deg.C) |
| Engine speed [Engine Speed] | 80 rpm | - |
| 12 volt battery voltage [Battery] | 10 V | 15.1 V |
[ ]: HDS Parameter
Malfunction Threshold
Despite there is no feedback from rocker arm oil pressure switch, the switching is active for at least 500 milliseconds.
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 stuck
- Rocker arm oil control valve failure
Confirmation Procedure
Operating Condition
Start the engine. Hold the engine speed [Engine Speed] at 3, 000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, the freeze data, and the on-board snapshot are stored in the PCM memory.
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.