P1494

Tests 546 - 550:

Tests 551 - 554:

SYMPTOM
P-1494 LEAK DETECTION PUMP SWITCH OR MECHANICAL FAULT

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

SET CONDITION
The state of the switch does not change when the solenoid is energized.

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 defective
- LDP wiring harness intermittent defect
- LDP wiring harness observable def
- LDP vacuum hose leaking or obstructed
- Powertrain control module defective