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Discussion Starter #1 (Edited)
I searched and read Auto Tranny pages. Some members posted similar issues but never the solution they ended up with. So here it is ...

2009 Cobalt LT - 4 speed automatic - currently only 58K on it.
Tranny Pan flush at 47K last year - filter not done.

Cold= delayed (3 sec.) engagement into D gear.
Warm = longer delayed (5 sec.) engagement into D gear.
Hot = no engagement into D gear. None of the forward gears engage. I put shifter in neutral - rev to
2000 rpm. and place in D about 1500 rpm with my foot on break - about 7 seconds later - it will
engage. Of course everyone else says I need to rebuilt tranny. I don't think so.

No check engine light. No codes via OBD2 reader. Always drives great once in Drive gear. Removed Pan today and changed fluid & filter - ensured fluid level. Still the same. In stumped and so is my mechanic.
 

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Check the harness that runs by the thermostat for chafing. Not all readers will read U codes, You may have lost of communication between BCM and TCM ( slow GMLan ). You could try re-seating the connectors on the BCM.
 

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Thankx Coby, will check the harness as soon as I can.

I fairly confident my mech's scanner would catch all the codes (although I admit I don't know what U stands for). Its Snapon stuff (the OBD2 equipment anyway) and he does seem to cough up ($) for new machines, etc. He did however say that he did not have GM software updates available to him.

---------- Post added at 06:12 PM ---------- Previous post was at 06:08 PM ----------

OK - I got know what U stands for - its bothering me ... lol
 

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Just a letter GM selected to identify communication codes because C was already used for Chassis. P for Powertrain and B for Body
 
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