DTC code: U0101 - "lost communication with TCM"

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Hi all, I got a GM 4T65E transmission in a '09 Impala with a 3.5L V6. Just did a OBDII scan for tranny codes since 4T65Es have an awful history. It comes up U0101 "lost communication with TCM " this means I can't see what's happening in the tranny. This could mean wiring / connector problems between modules stashed in the intake air plenum. However, just yanking cables out without a "heads up" could make it worse. Anyone worked on this problem before? Thanks!!
 
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Sounds like a can bus problem, it being an 09 and all. First rule of no comm, check all power and grounds. You must load them with a test light. DVM not good enough. Then check resistance of can bus terminators. Also worth checking fuses with test light, too.
 
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9 times out of 10 this code will be a history code (not current) and will not come back. Module traffic on the bus may have been too high for a given moment and the TCM just happened to be the module that could not communicate at that time. It happens on our new vehicles at the plant at times, we check all connections and clear codes. If is is a current code then you do need to look deeper and looking in the air box ECM/TCM connections is a good 1st place to look.
 
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Originally Posted By: GMBoy
9 times out of 10 this code will be a history code (not current) and will not come back. Module traffic on the bus may have been too high for a given moment and the TCM just happened to be the module that could not communicate at that time. It happens on our new vehicles at the plant at times, we check all connections and clear codes. If is is a current code then you do need to look deeper and looking in the air box ECM/TCM connections is a good 1st place to look.
GM usually puts out new calibrations for cars that are prone to the false codes. Easy to update if you have a SAEJ2534 passthru device like a cardaq2 or something.
 
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Originally Posted By: KingCake
Originally Posted By: GMBoy
9 times out of 10 this code will be a history code (not current) and will not come back. Module traffic on the bus may have been too high for a given moment and the TCM just happened to be the module that could not communicate at that time. It happens on our new vehicles at the plant at times, we check all connections and clear codes. If is is a current code then you do need to look deeper and looking in the air box ECM/TCM connections is a good 1st place to look.
GM usually puts out new calibrations for cars that are prone to the false codes. Easy to update if you have a SAEJ2534 passthru device like a cardaq2 or something.
That' true so I checked for 2009 Impala but there are no software/cal updates for this issue.
 
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Originally Posted By: GMBoy
Originally Posted By: KingCake
Originally Posted By: GMBoy
9 times out of 10 this code will be a history code (not current) and will not come back. Module traffic on the bus may have been too high for a given moment and the TCM just happened to be the module that could not communicate at that time. It happens on our new vehicles at the plant at times, we check all connections and clear codes. If is is a current code then you do need to look deeper and looking in the air box ECM/TCM connections is a good 1st place to look.
GM usually puts out new calibrations for cars that are prone to the false codes. Easy to update if you have a SAEJ2534 passthru device like a cardaq2 or something.
That' true so I checked for 2009 Impala but there are no software/cal updates for this issue.
Bummer. Was worth a shot.
 
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Hi all, The lost communication U0101 was found when I scanned the Traction control module, ie it's not getting data from the TCM, so it posted a code. Seems to be current. When I scanned the TCM directly, no codes. > 131,000 miles > no trouble light > drives OK If I'm to check grounds and +12 V, what pins on the connectors do I ID for that? Any Pics for that or diagrams? Thanks
 
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I had a U-code when my alternator died on me (everything lost power, including the OBD system, hence the no communication)
 
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