Author Topic: 97 ZJ OBD1 code 12  (Read 3354 times)

SteveTheFolkie

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97 ZJ OBD1 code 12
« on: September 06, 2015, 12:38:30 pm »
When I go on long (>6 hour) highway trips it's inevitable that I'll get a CEL code of 12 "12 - Direct battery input to PCM was disconnected within the last 50 Key-on cycles. " - curious how the direct battery input to the PCM can be disconnected while doing 80MPH on I81!  Any ideas?  It doesn't impact performance and I'm still getting 19MPG on trips to/from Gallatin TN (where, by the way, the gas is $1.97 gal) - just like to figure out why on long road trips I throw the same CEL!

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Steve

SteveTheFolkie

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Re: 97 ZJ OBD1 code 12 -- found the source!
« Reply #1 on: October 21, 2015, 05:46:29 pm »
So she started cutting out (dead) when I'd hit a big bump (living in PA that happens a lot!) - started tracing the wiring (hood up, engine running, start shaking the wiring) apparently dodgy wiring by the previous (only other) owner caused the issue - replaced a wire nut last weekend with a soldered joint and shrink tube - no issues since in spite of yanking on the harness - note that when she cut out there was no CEL and she started right up - but damned inconvenient - if you were behind me in Dover last Wednesday apologies in advance (there was a lifted red TJ behind me when she died at the light on Canal) - no more nonsense

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Steve

SteveTheFolkie

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Re: 97 ZJ OBD1 code 12
« Reply #2 on: January 05, 2016, 04:29:28 pm »
Curious about this - it still happens from time to time in my ZJ - apparently it means that the ignition has lost power sometime during the last 50 key cycles - it tends to go away after a couple of start cycles without disconnecting the negative terminal - has no impact on performance but I'm one of those irritating people who likes to know why something is happening - weather doesn't matter, velocity doesn't matter, road (or lack there of) doesn't matter - I can be pulling out of an ACNB onto 30, it'll come on; I can be doing 75MPH on I81, it'll come on, rain, snow, hot, cold - any ideas what I can check to eliminate this occasional fly in the ointment of what is otherwise a very trouble free ride?  My wife says don't worry about it, my friends say don't worry about it and my mechanic says don't worry about it (maybe the best thing to do would be to remove the CEL bulb!) -

Thanks in advance

Steve