the jeeps all have ASD relays 1991 up
this is the no crash and burn relay (purpose)
it cuts spark and fuel
if key (no pun) devices in the EFI fail hard. preventing fuel fires 99%
using a real scan tool most times we can see why it fails, (P03xx codes?) most newer jeeps have DTC error code called ASD overload. mine does.
error 42 ,1995 or P0685 , 1999
Read more: https://www.autocodes.com/p0685_jeep.html
but not always.
we can test the ASD to see if it is dropping off line
the 02 sensor wins the award for killing the ASD< if the O2 heater or wires short , the ASD drops off line. engine dead.
02 sensors or the wires lOVE TO SHORT> it;s their thing !
one simple trick here is unplug the o2 sensor, and crank.
not hot , only engine cold. be safe.
this is the no crash and burn relay (purpose)
it cuts spark and fuel
if key (no pun) devices in the EFI fail hard. preventing fuel fires 99%
using a real scan tool most times we can see why it fails, (P03xx codes?) most newer jeeps have DTC error code called ASD overload. mine does.
error 42 ,1995 or P0685 , 1999
Read more: https://www.autocodes.com/p0685_jeep.html
but not always.
we can test the ASD to see if it is dropping off line
the 02 sensor wins the award for killing the ASD< if the O2 heater or wires short , the ASD drops off line. engine dead.
02 sensors or the wires lOVE TO SHORT> it;s their thing !
one simple trick here is unplug the o2 sensor, and crank.
not hot , only engine cold. be safe.
http://www.fixkick.com