Advanced Diagnostics

Advanced Diagnostics

DTC P2648: Rocker Arm Oil Control Solenoid Circuit Low Voltage (Engine Type: K20Z3)






General Description
The VTEC system activates the rocker arm oil control solenoid by command from the engine control module (ECM), and it charges/discharges the hydraulic circuit of the VTEC mechanism that switches valve timing between low and high. If the return signal is OFF (low) when the ECM outputs the ON (high) signal to the rocker arm oil control solenoid, the ECM detects a malfunction and a DTC is stored.

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






Enable Conditions






Malfunction Threshold
The return signal is OFF (low) for at least 1.1 seconds when the ECM outputs the ON (high) signal to the rocker arm oil control solenoid.

Driving Pattern

1. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on.
2. Drive the vehicle in a lower gear at 4,000 rpm or more with a manifold absolute pressure (MAP) value of 12 kPa (3.5 in.Hg, 90 mmHg) or more for at least 7 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 ECM 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.