Jeep Grand Cherokee P1388 ASD Relay Circuit

Discussion in 'General Tech' started by 85TrailRunner, Sep 26, 2010.

  1. 85TrailRunner

    85TrailRunner Member

    Joined:
    Mar 16, 2007
    Location:
    Monroe
    I just finished putting the rebuilt 4.0 back into my '98 Grand Cherokee & although its not showing a check engine light on the dash when I search for codes it shows a P1388 Auto Shutdown Relay Circuit code. The Jeep starts & runs kind of rough but I figured since its sat for several years & the rebuild engine sat for over a year that'll happen & should get better once driven some. After letting it sit & run its already gotten better than it first was. I drove it around the neighborhood the other night & it did fine.

    Is the relay the same as the other relays so could some "swapnostics" solve this problem? Should this relay test the same as other relays? Or could the problem be somewhere else besides in the ASD relay itself? Thanks for any help.
     
  2. willness33

    willness33 Well-Known Member

    Joined:
    May 3, 2005
    Location:
    Alexis,NC
    Unless I'm mistaken, the ASD relay controls several critical engine systems, including the fuel pump. If the ASD relay was bad, you'd have a non-running engine. You could swap any of the other relays in it's place, but I doubt you'd see any difference in performance. If you're not currently throwing a code, I wouldn't worry about it. You could have a stored ASD code if you had the ingition power on at any time with something in the harness unplugged or relay's pulled.
     
  3. 85TrailRunner

    85TrailRunner Member

    Joined:
    Mar 16, 2007
    Location:
    Monroe
    I'm just worried about trying to get it to pass inspection, the check engine light isn't lit up but the code is still there even after I reset it. Didn't know if it was a common thing on Jeeps or not, thanks for the reply. :beer:
     

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