Liberty Sport 2WD L4-2.4L VIN 1 (2002)
Main Relay (Computer/Fuel System): Description and Operation
AUTO SHUT DOWN RELAY
PCM Output
The 5-pin, 12-volt, Automatic Shutdown (ASD) relay is located in the Power Distribution Center (PDC). Refer to label on PDC cover for relay
location.
The ASD relay supplies battery voltage (12+ volts) to the fuel injectors and ignition coil(s). With certain emissions packages it also supplies 12 -
volts to the oxygen sensor heating elements and the oxygen sensor heater relay
The ground circuit for the coil within the ASD relay is controlled by the Powertrain Control Module (PCM). The PCM operates the ASD relay by
switching its ground circuit ON and OFF.
The ASD relay will be shut-down, meaning the 12 - volt power supply to the ASD relay will be de-activated by the PCM if the ignition key is left
in the ON position. This is if the engine has not been running for approximately 1.8 seconds.
ASD Sense - PCM Input
A 12 volt signal at this input indicates to the PCM that the ASD has been activated. The relay is used to connect the oxygen sensor heater
elements, oxygen sensor heater relay ignition coil and fuel injectors to 12 volt + power supply.
This input is used only to sense that the ASD relay is energized. If the Powertrain Control Module (PCM) does not see 12 volts at this input when
the ASD should be activated, it will set a Diagnostic Trouble Code (DTC).
