Fuel Pump Relay: Description and Operation

Fuel Pump Relay:

Fuel Pump Relay
The Fuel Pump (FP) relay (Figure 7) supplies voltage to the FP when activated by the Powertrain Control Module (PCM). The PCM activates the FP relay for five seconds after turning the ignition key ON, and when the engine is cranking or running. The PCM deactivates the FP relay 1.5 seconds after the engine stops. The voltage supplied from the FP relay allows the FP motor to operate. When the PCM receives a 120 degree signal from the Camshaft Position (CMP) sensor, it knows that the engine is rotating, and causes the FP relay to activate. When activated, the FP relay supplies the FP with voltage which allows it to operate continuously as long as the engine is running. If the PCM does not receive a 120 degree signal when the ignition switch is ON, the engine is stalled. The FP relay is deactivated and prevents battery discharging, thereby improving safety.