Leak Detection Pump Solenoid Circuit (OBD II)

Name of Code:
Leak Detection Pump solenoid Ckt

When Monitored:
Ignition on and battery voltage greater than 10.4 volts.

Set Condition:
The state of the solenoid circuit does not change.

Theory of Operation:
The PCM provides ground for the solenoid and 12-volts comes from ignition output. When the solenoid is energized, it allows engine vacuum to enter the pump and draw the diaphragm up, thus allowing atmospheric pressure to enter the pump cavity. When the solenoid is de-energized it vents the engine vacuum thus permitting the spring to drive the diaphragm down, forcing air out of the pump cavity into the vent system. When the solenoid is energized and de-energized, the cycle is repeated which creates flow in a typical diaphragm pump fashion.

Possible causes:
- Open or shorted LDP Solenoid control circuit
- Leak detection pump solenoid failure
- Open fused ignition switch output
- PCM failure
- Connectors
- Wires