Grand Caravan V6-3.3L VIN E Flex Fuel (2007)
Ignition Shut Down Relay (For Antitheft): Description and Operation
The engine switched battery (NGC vehicles) informs the PCM when the ASD relay energizes. A 12 volt signal at this input indicates to the PCM that the
ASD has been activated. This input is also used to power certain drivers on NGC vehicles.
When energized, the ASD relay on NGC vehicles provides power to operate the injectors, ignition coil, generator field, O2 sensor heaters (both upstream
and downstream), evaporative purge solenoid, EGR solenoid (if equipped) wastegate solenoid (if equipped), and NVLD solenoid (if equipped).
The ASD relay also provides a sense circuit to the PCM for diagnostic purposes. If the PCM does not receive 12 volts from this input after grounding the
control side of the ASD relay, it sets a Diagnostic Trouble Code (DTC). The PCM energizes the ASD any time there is an engine speed that exceeds a
predetermined value (typically about 50 rpm). The ASD relay can also be energized after the engine has been turned off to perform an O2 sensor heater
test, if vehicle is equipped with OBD II diagnostics.
As mentioned earlier, the PCM energizes the ASD relay during an O2 sensor heater test. On NGC vehicles it checks the O2 heater upon vehicle start.
The PCM still operates internally to perform several checks, including monitoring the O2 sensor heaters.