ASD is tricky on jeeps.
The Auto shutdown,relay.
what is it , how does it works is covered in the fsm. read it.
The ECU runs this RELAY, and if the ECU sees a gross error
it shuts this down, and the schematic there is clear as to what.
both spark and fueling.
here is what can drop it out.
1: crank sensor.
2: cam sensors or TDC ,etc.
3: sees spark dead or weak.
4: Immobilizer active. (failed)
as the book says , make sure spark is good for the 2 seconds cranking. (not after the 2seconds)
the ECU is programmed like this.
ECU creates spark,, using the crank/cam sensors at the time base
for 2 seconds
if the spark read back fails or the 2 sensors fail, the ecu shuts DOWN.
this is for fire prevention.
most other cars just cut the injectors, but not jeep
the drop the MAIN ASD relay.
using the check engine light flash codes, you can see which of the
3 failed, cranking for 5 second and releasing the key on all cars.
1996 and newer a scan tool is use to same effects.
now the 64,000 dollar qustion,
see page 8w-30-4
why does the ASD KILL THE IGNITION coil. easy.
1: it only guess it 2 seconds to make spark
2: if it cant,. it then drops the relay. killing fuel too.
3: this prevents the the crash and burn you see on TV.
so its 2 second permissive system. (or 3?) i forget exact seconds, its in then book and is short.
many dont know this. but is a fact.
now the flash codes.
crank for 5 seconds while in flash code mode
see emmisions page for how.
flash code 11 drops the ASD ! (cam or crank sensor dead)
code 54 cam signal dead?
code 43, spark bad.