Advanced Diagnostics

DTC P128A: Valve Pause System (VPS) Stuck OFF




General Description
Two rocker arm oil control solenoids open and close according to the commands from the powertrain control module (PCM), and oil pressure is applied to and then drawn from the valve pause system (VPS) to change valve timing and the operation of the valve.

The PCM monitors the oil pressure of the switching mechanism using an engine oil pressure (EOP) sensor and a rocker arm oil pressure switch downstream of the rocker arm oil control solenoid. The PCM compares the oil pressure based on the PCM command and the oil pressure condition of the EOP sensor and the rocker arm oil pressure switch to determine if the system is operating normally.




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




Enable Conditions




Malfunction Threshold

Confirmation Procedure with the HDS
Do the VTEC TEST in the INSPECTION MENU with the HDS.

Driving Pattern
1. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on.
2. Hold the engine speed between 1,000 rpm and 3,000 rpm for at least 5 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 PCM 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.