I’ve changed 3 transmission control modules in my 2016 Chevy impala.
One mechanic said MAYBE if I get an alternator and battery it would stop. He also stated he put in a bigger fuse to handle the voltage. The dealership of the Chevy said that it’s losing communication ( when I explained that I had the module replaced 2x in two weeks) but that it “ just happens”. I would like to know if anyone else with this car has this issue with the module or if they know why I have gone through so many?
No experience w/ that car myself, but I’ll offer up some guesses which might be helpful.
Fuses regulate the current, not the voltage. For safety reasons fuses must always be sized according to the circuit’s wire diameter. Unless the wire diameter was increased at the same time (guessing this is unlikely), fuse amperage should remain the same as came from the factory.
They are probably talking about the car’s CAN bus, which is sort of like the internet, except just between the gadgets inside the car. Just like the internet, intra-car connectivity can be lost for no apparent reason. Of course there’s always a reason, but often the reason can’t be found without expensive shop testing, which isn’t economically practical for the typical car owner. The shop tech might be able to get it working again by resetting the connection. Maybe they’ll also disconnect and reconnect some pertinent connectors.
That’s possible. Usually a failed battery/charging system test would precede replacing the two parts.
Assuming you are representing the shop’s statements correctly and in an unbiased manner, I’m thinking this shop isn’t the best for this particular problem. Multiple TCMs failing isn’t completely unheard of either.
Your car is now at risk of catching on fire. Put the original fuse back and find a better mechanic.
2 Likes
You have not mentioned how many miles on the car, what the symptoms are, and any history of transmission services. Regarding the latter; my assumption is usually the norm. None. Depending upon the symptoms has anyone considered aged fluid, half clogged filter, etc? A half clogged filter opens up another can of worms… 
You need to have a proper diagnosis done and avoid this mechanic. Replacing the same part multiple times points to wild guessing (along with replacing battery/alternator) and what you were told about a bigger fuse is bad advice.
Find a long established independent transmission shop and let them take a look at it. And ind. trans shop does not mean AAMCO, Cottman’s, or any other chain.
3 Likes