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.
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HOMESERVICE MANUALSPLYMOUTH1984HORIZON L4-97 1.6L SOHCREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTRELAYS AND MODULES - POWERTRAIN MANAGEMENTRELAYS AND MODULES - COMPUTERS AND CONTROL SYSTEMSMAIN RELAY (COMPUTER/FUEL SYSTEM)DESCRIPTION AND OPERATION
1984 Plymouth Horizon L4-97 1.6L SOHC
Main Relay (Computer/Fuel System): Description and Operation
1984 Plymouth Horizon L4-97 1.6L SOHCSECTION Description and Operation
Location
The ASD relay is housed in the [1][2]Power Module.
Purpose
The Logic Module controls the ignition coil, fuel pump, fuel injector, and [1][2]power module, through the ASD relay, by grounding the relay.
Operation
The Logic Module monitiors the distributor pick-up signal, and if the Logic Module senses this signal (engine is running), the logic module grounds the ASD relay.
If the Logic Module does not sense a distributor pick-up signal, the logic module removes the ASD relay ground (within one second), interrupting power to the fuel pump, fuel injector, and ignition coil.
This "Shutdown" is intended to stop fuel flow and ignition spark in the event of an accident.
RENDER: 1.0x
NO RELATED
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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.