Neon L4-2.0L DOHC (1996)
Automatic Shut Down (ASD) Relay: Description and Operation
Related Trouble Codes and Set Conditions
Auto Shutdown Relay Control Circuit
Name of Code:
Auto Shutdown Relay Control Circuit
When Monitored:
With the ignition key on and battery voltage greater than 10 volts.
Set Condition:
An open or shorted condition is detected in the auto shutdown relay control circuit.
Theory of Operation:
The automatic shutdown relay (ASD) controls the 12 volt source to the fuel injectors, ignition coil(s), oxygen sensors, and the generator. The relay
is located in the power distribution center (PDC). One side of the relay control coil is supplied with 12 volts when the ignition switch is turned to
the run position. The circuit is completed when the other side of the relay coil is grounded by the powertrain control module (PCM). The PCM
grounds the relay when the ignition switch is in either the run or crank position and engine RPM is detected. If engine RPM is not detected, the
PCM will remove the ASD relay control circuit ground.
Possible Causes:
-
Relay coil open or shorted
-
Fused ignition switch output circuit open
-
Auto shutdown relay control circuit open or shorted
-
Inoperative circuit driver in powertrain control module
-
PCM failure
-
Connector terminals
-
Connector wires
No ASD Relay Output Sensed at PCM
Name of Code:
No Auto Shutdown (ASD) Relay Output Voltage At PCM
When Monitored:
With the ignition key on and battery voltage greater than 10 volts.
Set Condition:
No voltage sensed at the powertrain control module when the auto shutdown relay is energized.
Theory of Operation:
When the ASD relay is energized, the relay contacts connect the fused B(+) circuit to the relay output circuit. The powertrain control module is
connected in parallel with the ASD relay output circuit. This connection provides the PCM with a circuit to monitor the ASD relay output state.
Whenever the PCM energizes the ASD relay, it checks the feedback circuit to ensure voltage is present at the ASD relay output. If voltage is not
present, a trouble code is set.
Possible Causes:
-
ASD relay output circuit open
-
Fused B(+) circuit open
-
ASD relay
-
Failed PCM
-
Connector terminals
-
Connector wires