P1494

Tests 617 - 622:

Tests 623 - 625:

SYMPTOM
P-1494 LEAK DETECTION PUMP SW OR MECH FAULT

WHEN MONITORED
Immediately after a cold start, with ambient temperature between 40 deg F and 90 deg F and coolant temperature within 10 deg F of ambient temperature.

SET CONDITION
The state of the leak detection pump switch is not in its expected state at key-on (engine not running). Or, following an engine start, a change in switch state is not seen when the LDP solenoid is energized to pull the pump diaphragm to its "up" position

POSSIBLE CAUSES
- Fused ignition switch out circuit open
- LDP pressure switch circuit short to ground
- LDP switch sense circuit open
- LDP wiring and/or connectors OBS def
- LDP wiring harness intermittent failure
- LEAK or obstruction in vac hose
- LEAK detection pump defective
- PCM def (LDP system)