tburk

Well I recently posted on here earlier in the week about my jeep just not starting one morning. No fuel psi on the rail, no pump run situation. Had spark, etc. I troubleshot it down to the PCM with the help online here and my service manual. Replaced the PCM and Got it going wednesday night and drove it to and from work twice with no problems till I left work today. It died and wouldnt restart. I had it towed and when I got it off of the truck it started right up. Has started and restarted about 6 times since. I decided to read the codes and I got 0463 and 1388. I expect the 0463 code my gas guage hasnt worked for some time. the 1388 one is for the ASD ckt and it had me wondering tho so while the darn thing was / is still starting I swapped back in the old PCM and what do you know......it started so that rules that one out. So while I start to draw out the auto shut down ckt, has anyone else seen this?

Fun times in 19degree weather..

freegdr

is this auto shut down part of the alarm or a inertia switch?

tjwalker

First thing I would do if this were my vehicle would be to swap the ASD relay (located in the power distribution center under the hood) with another relay like the AC relay or e-fan, something non-critical. If this resolves your intermittent problem, replace that relay that you swapped out. Here is more.

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A P1388 is an open or short detected in the ASD (automatic shutdown) relay control curcuit.

SYMPTOM: P1388-AUTO SHUTDOWN RELAY CONTROL CIRCUIT

WHEN MONITORED
With ignition key ON and battery voltage above 10.4 volts .

SET CONDITION
An open or shorted condition is detected in the ASD Relay control circuit.

POSSIBLE CAUSES

Intermittent condition
ASD relay resistance
Fused ignition switch output circuit
ASD relay control circuit shorted to ground
ASD relay control circuit open
PCM

freegdr

what is it for the asd

tburk

All, I did put in a new ASD relay to rule that out. Drawing out the ckt on one sheet of paper, it looks to me that the power to the PCM is fed through FU 20. This fuse also provides power to the coil. Since I have spark even when it wont start and knowing this fuse is good, I suspect the DG/OR wire that feeds power to the PCM. If the coil is getting voltage, but the PCM isnt, then I wouldnt get the fuel pump relay to turn on (by the PCM) nor would I get any fuel injector action. I would be able to turn the motor over, and get spark, just no fuel or injector pulse due to the PCM lacking power??

Does this logic sound reasonable?

Todd