Fuel Pump Circuit Wiring Diagram (2002-2005 3.1L V6 Buick Century)

APPLIES TO: This fuel pump circuit wiring diagram applies to the following vehicles:

• 3.1L V6 Buick Century: 2002, 2003, 2004, 2005.

Basic Operating Theory Of The Fuel Pump Relay

The fuel pump relay is responsible for delivering battery power to the in-tank fuel pump under the PCM's command.

Every time you turn the ignition key to the ON position, the PCM briefly energizes the relay for about 2 seconds. This is known as the fuel pump prime cycle, and its purpose is to build fuel pressure before the engine starts.

If the engine isn't cranked, the PCM de-energizes the relay after the prime cycle ends. Once the PCM detects crankshaft position signals during cranking or while the engine is running, it energizes the relay again and keeps it energized as long as those signals continue.

Because the PCM continuously monitors engine rotation, it immediately turns the fuel pump relay off if the engine stalls. This prevents the fuel pump from continuing to operate when the engine is no longer running.

A defective fuel pump relay may prevent the engine from starting, cause intermittent stalling, or keep the fuel pump from running during the initial 2-second prime cycle.

FUEL PUMP TESTS: How To Test The Fuel Pump (1994-2005 3.1L V6 Buick Century).

Other Fuel Pump Wiring Diagrams

• Fuel Pump Circuit Wiring Diagram (1994-1995 3.1L V6 Buick Century).
• Fuel Pump Circuit Wiring Diagram (1996 3.1L V6 Buick Century).
• Fuel Pump Circuit Wiring Diagram (1997 3.1L V6 Buick Century).
• Fuel Pump Circuit Wiring Diagram (1998-1999 3.1L V6 Buick Century).
• Fuel Pump Circuit Wiring Diagram (2000-2001 3.1L V6 Buick Century).

More 3.1L V6 Buick Century Tutorials

You can find a complete list of 3.1L V6 Buick Century tutorials and wiring diagrams in this index:

• 3.1L V6 Buick Century Index of Articles.

Here's a sample of the tutorials you'll find in the index:

• How To Test The TPS With A Multimeter (1997-2005 3.1L V6 Buick Century).
• Common Causes Of Spark Plug Failure (1994-2005 3.1L V6 Buick Century).
• How To Test For A Blown Head Gasket (1994-2005 3.1L V6 Buick Century).
• How To Test Engine Compression (1994-2005 3.1L V6 Buick Century).