P1494

Test 1:

Tests 2 - 5:

Tests 6 - 7:

SYMPTOM
P1494 - LEAK DETECTION PUMP SWITCH OR MECHANICAL FAULT

WHEN MONITORED
Immediately after a cold start, with ambient temperature between 40 °F and 90 °F and coolant temperature within 10 °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 output circuit open
- LDP pressure switch circuit shorted to ground
- Leak detection pump switch sense circuit open
- Leak detection pump
- LDP wiring harness intermittent defect
- LDP wiring harness observable defect
- LDP vacuum hose leaking or obstructed
- Powertrain Control Module