Advanced Diagnostics

Advanced Diagnostics - DTC P1024: Valve Pause System (VPS) Sticking On






General Description
Fuel-cut is done only for the cylinder that is judged as misfiring by crank pulse fluctuation monitored by the powertrain control module (PCM). This is further monitored by using the A/F sensor to judge and distinguish if the misfire occurred because of a failure in the valve pause system (VPS).

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






Enable Conditions






Malfunction Threshold
When the A/F sensor output does not change and the calculation value of a correction coefficient (KAF) of A/F feedback remains about 0.85 to 1.0.

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 P or N) until the radiator fan comes on.
2. Hold the engine speed between 2,000 - 6,500 rpm for at least 30 seconds.

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected, a Pending DTC, a Confirmed DTC, and the freeze data are stored in the PCM memory. The MIL does not come on.

Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.