Troubleshooting a Fuel Pump Relay in a Corsica

The first thing to check when troubleshooting a fuel pump relay in a Corsica is the fuse for the fuel pump. The fuse is located in the fuse relay box. If the fuse is good, pull the relay out of the socket. There will be at least four female terminals that it is plugged into. Set a voltmeter to the 20-volt scale. Two jumper wires with alligator clips will also be needed. With the ignition key off, check the terminals for power. There should be one terminal with power with the key off. If not, there is a wiring problem under the fuse block between the fuse and the power terminal.

If there is power at one terminal, a helper will be needed for the next test. When the key is turned on, the computer will allow the fuel pump to prime for two seconds. If the computer does not receive a signal from the camshaft sensor indicating the engine is turning over or running, it will shut the power off for the pump. This is for safety reasons. In an accident, if the engine fails, the pump will be shut off to prevent fire.

Have your helper turn the key on and then off for five seconds for the computer to reset. While he is doing this, check for power at one more terminal for these two seconds. If there is no power, the problem is either in the ignition switch or the security system. If the security system is activated it will turn the power off to the relay so the car cannot be started. If there is power, turn the knob on the voltmeter to OHMS and turn the key off. Remember which terminals were hot, if not retest and memorize these terminals. Use the ohmmeter to test for continuity to ground on the two remaining terminals.

The terminal that does not go to ground will go to the fuel pump. Using the jumper wire, jump the terminal that was hot all the time to the terminal that was not a ground. The fuel pump should come on. If you cannot hear the fuel pump come on, open the gas cap and listen for the pump. If the pump is not working the pump itself--or possibly the wiring is bad, though it is not likely that the wiring is bad. With the jumper in place, jack the car up enough to get under the gas tank and pull the fuel pump connector at the back of the tank and check for power. If the fuel pump is working replace the relay.