Allison Tranny codes?

Question

Can someone tell me what these Allison Transmission codes mean?
The codes for the transmission are #U2105 & U0100
This is a 2500 Tranny. Vintage 2001. The Allison shop where my friend took his Motor Home to claims they have never seen them before and offered no help which sounds very strange. I did a search and what I find does not make any sense to me so, maybe someone knows the answer. Thanks for your help

redsb3 · Answer

U2105 should be a code that means the tranny control module has lost communication with the ECM (engine control module).  U0100 means tranny has lost communication with ECM &amp; PCM modules.  This could be anything from loose connectors on either module to weak batteries, bad ground.  You can see these codes on light duty trucks, you probably don't see these codes on the 3000-4000 series Allisons.

wittmeba · Answer

This might give you enough info to figure it out.http://www.epa.ohio.gov/portals/27/echeck/docs/Techtalk_fall07.pdf

funtime · Answer

Thanks Guys for the information as it was very much appreciated and thanks for the link. I will keep that link handy.

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Allison Tranny codes?

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