Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1994 Eagle Vision V6-201 3.3LFACTORY OEM SERVICE PROCEDURE
Main Relay (Computer/Fuel System): Description and Operation
LOCATION
Relay is mounted in the power distribution center.
PURPOSE
Relay supplies battery voltage to fuel pump relay, fuel injectors, ignition coil, and O2 sensor heating element when energized by Powertrain Control Module (PCM).
OPERATION
The PCM energizes Auto Shutdown (ASD) relay by supplying relay ground, when ignition switch is in START or RUN position and PCM is receiving a reference signal from distributor.
When the ground is applied, the relay is energized, and voltage is allowed to flow to fuel pump, fuel injectors, ignition coil, generator field winding, and O2 sensor heating element.
When PCM does not receive reference signal from ignition system, (indicating engine is not running), then the PCM interrupts relay ground circuit and no voltage is supplied to fuel pump, fuel injectors, ignition coil, generator field winding, and O2 sensor heating element.
The PCM controls fuel pump relay and ASD relay simultaneously, through same ground circuit.
Relay is mounted in the power distribution center.
PURPOSE
Relay supplies battery voltage to fuel pump relay, fuel injectors, ignition coil, and O2 sensor heating element when energized by Powertrain Control Module (PCM).
OPERATION
The PCM energizes Auto Shutdown (ASD) relay by supplying relay ground, when ignition switch is in START or RUN position and PCM is receiving a reference signal from distributor.
When the ground is applied, the relay is energized, and voltage is allowed to flow to fuel pump, fuel injectors, ignition coil, generator field winding, and O2 sensor heating element.
When PCM does not receive reference signal from ignition system, (indicating engine is not running), then the PCM interrupts relay ground circuit and no voltage is supplied to fuel pump, fuel injectors, ignition coil, generator field winding, and O2 sensor heating element.
The PCM controls fuel pump relay and ASD relay simultaneously, through same ground circuit.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.