Neon L4-2.0L VIN C (1997)
Automatic Shut Down (ASD) Relay: Description and Operation
Fig. 20 Power Distribution Center (PDC)
PURPOSE
The Automatic Shutdown (ASD) relay supplies battery voltage to the fuel injectors, electronic ignition coil and the heating elements in the oxygen
sensors.
OPERATION
A buss bar in the Power Distribution Center (PDC) supplies voltage to the solenoid side and contact side of the relay
The ASD relay power circuit contains a 20 amp fuse between the buss bar in the PDC and the relay.
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The fuse also protects the power circuit for the fuel pump relay and pump. The fuse is located in the PDC.
The PCM controls the ASD relay by switching the ground path for the solenoid side of the relay on and off.
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The PCM turns the ground path off when the ignition switch is in the OFF position.
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When the ignition switch is in ON or START, the PCM monitors the crankshaft and camshaft position sensor signals to determine engine
speed and ignition timing (coil dwell).
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If the PCM does not receive crankshaft and camshaft position sensor signals when the ignition switch is in the Run position, it will de-energize
the ASD relay
The ASD relay is located in the PDC (Fig. 20). The inside top of the PDC cover has a label showing relay and fuse identification.
CIRCUIT OPERATION
The Automatic Shut Down (ASD) relay is located in the Power Distribution Center (PDC). Power for the coil and contact side of the relay is
supplied on circuit A14. This circuit is HOT at all times and protected by a 20 Amp fuse located in the PDC.
The Powertrain Control Module (PCM) controls the ground path for the coil side of the relay on circuit K51. This circuit connects to cavity 67 of
the PCM.
When the PCM supplies the ground path on circuit K51 the contacts in the relay CLOSE connecting circuits A14 and A142. The A142 circuit is
spliced and supplies power to the generator, fuel injectors, PCM, ignition coil, and heated oxygen sensors.
