96 ZJ TCM Reset? Overdrive not working? - JeepForum.com
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Unread 12-11-2012, 06:41 PM   #1
1999blacksvt
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Location: Warrensburg, Missouri
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96 ZJ TCM Reset? Overdrive not working?

Hey everyone. I had recently changed out my radiator, trans filter, and replaced the fluid. Right after I noticed crappy shifting and slipping so I put more fluid in it and she was g2g. On a 2 hour trip my trans over temp starting flashing and my overdrive went out.

As of now overdrive still does not work. I noticed that my trans cooler hose was twisted so I untwisted it and reset the battery. It still won't go into overdrive. What are my options? Can I try resetting the TCM or does resetting the battery do this?

What else could it be? Overdrive fried?

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Unread 12-13-2012, 07:47 PM   #2
1999blacksvt
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Anyone?
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Unread 12-13-2012, 08:04 PM   #3
ZeeJay1997
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You dont have a TCM. The PCM does that on >95

Never heard of a trans over temp on a ZJ, but I'm a 2wd guy

Is the green LED illuminated on the OD button?
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Unread 12-13-2012, 08:10 PM   #4
1999blacksvt
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Yes it is upon startup. Letting the battery reset helps, but eventually the light comes on upon start up and only goes off if I press it off. It shifts fine but O/D never kicks in. I've heard when these go into safe mode during over heating the O/D kicks off, however I read to reset the TCM. But if the PCM controls it, that means unhooking the battery would reset it correct?
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Unread 12-13-2012, 08:38 PM   #5
ZeeJay1997
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Quote:
Originally Posted by 1999blacksvt View Post
But if the PCM controls it, that means unhooking the battery would reset it correct?
No, The control module determines transmission shift points based on input signals from the transmission thermistor, transmission output shaft speed sensor, crankshaft position sensor, vehicle speed sensor, and throttle position sensor.

Cycle the ignition key On - Off - On - Off – On within 5 seconds and see if the odometer shows any codes.
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Unread 12-19-2012, 06:08 PM   #6
1999blacksvt
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Pulled a 12 and 55 codes. So those seem to be normal. What next?

Last edited by 1999blacksvt; 12-19-2012 at 06:25 PM..
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