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.
Automatic Shutdown Relay
Automatic Shutdown (ASD) relay is located in Power Distribution Center (PDC) near the battery or next to radiator coolant recovery bottle. For ASD relay location within PDC, refer to PDC cover label.
ASD relay supplies battery voltage to fuel injectors, generator field winding, and ignition coil. The relay contacts are normally open.
Power is supplied to relay coil when the ignition switch is turned on. The PCM controls the ground circuit, which energizes the relay coil and closes the relay contacts.
The PCM will only ground the relay when ignition switch is in the Run or Start positions, and activity is sensed through the crankshaft position sensor and the camshaft position sensor in the distributor. If the PCM senses the RPM signal has stopped, it will remove the ground from relay coil, which will cause the contacts to open and remove power from the circuit.
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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.