ECU-TCM PRNDL switch issue not like any other! PLEASE HELP!

[tnelson013]

Hey guys,

ive searched all over the forrums and have seen a couple people with this issue but i cant seem to fix my problem....

Put cab lights on my truck and had a wire short. My ABS, parking brake light, and a service 4wd alert came on and my PRNDL light went out. tripped a code U0101 TCM lost communication. So i got on here and started reading. Today I picked up a new ecm-tmc thinkin for sure that was my problem. put it in the truck and nothing. had my batteries checked and 1 was bad. Bought a new battery put it in and nothing.
heres whats different about my issue compared to the others: my truck will not start. i turn the key over and i have zero cranking power and i cannot clear the U0101 code (with edge CTS).

the only thing i can think of that i havent replaced is the NSBU switch on the driver side of the tranny. Would this be my next step or am i missing something simple? Could the company have written in the wrong vin on the new ecu-tcm?None of my fuses are visably blown. again, i cannot even start my truck unlikw the other forrums i have read with people having the same issue.

i refuse to take my truck to a dealership. ive had nothing but bad experiences with them. Any help would be greatly appreciated.

[tnelson013]

i found anither thread with same issue of truck not starting but there was not a solution. any ideas on whst i should do?

[whiteoutlly]

Sure sounds like your burnt out your TCM. I'll almost bet on it.

[tnelson013]

ive replaced the tcm and before i put the new one in i unhooked the power source for my cab lighta. im about 98% sure thats what caused the short in the first place. i wouldnt think it was my prndl switch because my prndl lights in the instrument panel are still lit and my truck should still start if that was out. and i think that switch being bad would trip a P code and not a U code.
is the new tcm bad? What should i do next?

[terryk]

Wiggle the key and see if it does anything. Also, cycle the tilt column up and down. There are several circuits on the ignition switch and one is power for the TCM. You could have a back switch or bad connection. Mine did. I kept getting TCM comm errors.

Just a suggestion.

Edit: Forgot something. The TCM is powered via IGN 1. Can you check the voltage? I believe the fuse is post ignition switch so if it's low, it maybe indicate a faulty switch. Since the switch switches several circuits you can lose one (like TCM power) and not others.

[baconstruction]

if you dont get a gear selection on the dash the truck wont start most time because it does not know what gear it is in. However if you turn the key forward you should be able to clear the code.

Does your lights and radio come on?

[vinnie gillotti]

check all fuses teh check your wire harness behind alt for caffing and shorts.

[tnelson013]

its not the ignition or a rubbed wire. i hooked the new ecm up with the bad battery. had tounhook everything when iput the new battery in so the computer had the power to operate correcy. i got my truck running and everything is workin correctly. re routed my wires for the cab lights i put on and got them tucked away. thanks for all the advice

[terryk]

What exactly was wrong?

[tnelson013]

i thought my cab lights sjorted my ecu-tcm so i bought a new one. come to find out i had a bad battery that surged the internal grounding unit on the ecu and fried it. when i put the new one in there wasnt enough power in the battery to reboot the computer so i thought i had another problem. aftet i put the new batteries in i had to disconnect the ecu-tcm and reconnect for it to register.
my problem all along was a bad battery that fried my computer. it just happened to go out after i put my cab lights on. at first i was pretty lit about it but now with the new ecu i can change my driving pattern. went from 18-20mpg to 25mpg this morning on my way to work