P1494 Buick EVAP Leak Detection Pump Pressure Switch Condition

P1495 Buick EVAP Leak Detection Pump Solenoid Circuit Condition

Possible causes

– Leak Detection Pump (LDP) harness is open or shorted
– Leak Detection Pump (LDP) poor electrical connection
– Faulty Leak Detection Pump (LDP)

What about the obd code?

Malfunction is detected when the Powertrain Control Module (PCM) detected the pump solenoid did not change status when activated,

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Possible a noticeable fuel odor caused by the release of fuel vapors

P1495 Buick Description

The Evaporative emissions system is design to prevent the escape of fuel vapors from the fuel system. Leaks in the system, ca allow vapors to escape into the atmosphere. The leak detection system tests for EVAP system leaks and blockage.

During the self-diagnostics, the Powertrain Control Module (PCM) first checks the Leak Detection Pump (LDP) for electrical and mechanical faults. If the first checks pass, the PCM then uses the LDP to seal the vent valve and pump air into the system to pressurize it. If a leak is present, the PCM will continue pumping the LDP to replace the air that leaks out. The PCM determines the size of the leak based on how fast/long it must pump the LDP as it tries to maintain pressure in the system.

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