Purge Control Valve

The MS S52 system uses a purge valve that is sprung closed and powered open. This type of purge valve is required for OBD II compliancy and evaporative system leak detection tests. This type of valve also prevents vapors escaping into the atmosphere when the vehicle is not in use. The valve will not open under fuel vapor over pressure. The valves are cycled periodically during engine operation. The duty cycle of the purge valve solenoid may vary between 0-100 percent depending on engine operating conditions. Evaporative purge system is monitored for flow check after fuel system adaptation is complete and PCM oxygen sensor feedback is in closed loop. The diagnosis starts during normal purge operation. After the system has completed a purge cycle, the valve is cycled abruptly several times. In addition to the rich/lean shift, the engine idle speed will vary. If the predetermined values are reached, the system is functioning properly. The flow check will operate after oxygen sensors in closed loop, engine at idle speed and coolant temperature above set limit.