DeVille V8-4.9L VIN B (1995)
Fuel Pump Relay: Description and Operation
Fuel Pump Circuit
PURPOSE
The fuel pump relay allows the fuel pump to be energized by the Powertrain Control Module (PCM).
OPERATION
When the ignition is first turned "ON," the PCM energizes the fuel pump relay for two seconds. This allows the fuel pump to run for two seconds
and build up fuel pressure for cranking. The PCM then waits for ignition reference pulses from the Ignition Control Module (ICM). Once the
PCM sees reference pulses, the PCM energizes the fuel pump relay to run the fuel pump.
A faulty fuel pump relay may cause long cranking times and should set a Diagnostic Trouble Code.
