Evaporative Purge Valve Control

The introduction of the evaporative fuel vapors (HC) from the fuel tank is provided by the purge valve. There are two types used with the systems covered in this manual.

- Sprung Open - Powered Closed (M1.x and M3.x)
- Sprung Closed - Powered Open (M5.x and MS 41.x)

Regardless of the type, the purge valve receives operating power from the Main Relay and the ECM provides a modulated ground providing regulated purge vapors into the intake manifold system.







This example is of the sprung closed - powered open purge valve. This valve type is on all newer OBD II compliant systems for the purpose of closing the evaporative system when the engine is turned off.