ecu and tcm lost connection

26973 Views 15 Replies 6 Participants Last post by cart7881, 2 mo ago

alexisbarkl

Discussion Starter · Aug 19, 2013

Has anyone experienced lost connection problems between their tcm and ecu? My truck is fine for 10-20 minutes, with no problems and no check engine light and then ill notice the speedometer, odometer and gear lights stop working. Speedometer reads 0mph, odometer never goes up and my truck says I'm in 1st gear when I'm parked, driving, etc. The truck also goes into safe mode so I feel like I can reach a max of 50mph and pedal to the floor it does not go fast at all. The code is U0101, but I'm trying to avoid a brand new tcm altogether considering they'll connect for the first part of my drive and then say they're not connected I don't think its gone completely bad. Any suggestions?

09 Colorado, I5

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limequat

· #2 · Aug 19, 2013

alexisbarkl said:
Has anyone experienced lost connection problems between their tcm and ecu? My truck is fine for 10-20 minutes, with no problems and no check engine light and then ill notice the speedometer, odometer and gear lights stop working. Speedometer reads 0mph, odometer never goes up and my truck says I'm in 1st gear when I'm parked, driving, etc. The truck also goes into safe mode so I feel like I can reach a max of 50mph and pedal to the floor it does not go fast at all. The code is U0101, but I'm trying to avoid a brand new tcm altogether considering they'll connect for the first part of my drive and then say they're not connected I don't think its gone completely bad. Any suggestions?

09 Colorado, I5

Is anything else loosing network connection? For instance the tach or radio?

A TCM would actually be the first thing I try. You can get them used for very cheap and they do not need to be reprogrammed for your truck.

Supermodulation

· #3 · Aug 19, 2013

Any recent mods, new HU/chime module etc..?

rshadd

· #4 · Aug 19, 2013 (Edited)

Check for a loose connection at the TCM (#1).

T.C.M. MODULE (M30)

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alexisbarkl

Discussion Starter · #5 · Aug 19, 2013

limequat said:
Is anything else loosing network connection? For instance the tach or radio?

A TCM would actually be the first thing I try. You can get them used for very cheap and they do not need to be reprogrammed for your truck.

No, nothing else has lost connection. I was told its not smart to buy a used one and that new ones are 1,000.

alexisbarkl

Discussion Starter · #6 · Aug 19, 2013

Supermodulation said:
Any recent mods, new HU/chime module etc..?

No new mods

alexisbarkl

Discussion Starter · #7 · Aug 19, 2013

rshadd said:
Check for a loose connection at the TCM (#1).

T.C.M. MODULE (M30)

I have tried checking for a loose connection, but I have yet to unconnect and reconnect it to see if that helps, I know where to unconnect it just can't figure out how to unconnect it, cant get them apart.

rshadd

· #8 · Aug 19, 2013 (Edited)

alexisbarkl said:
I was told its not smart to buy a used one and that new ones are 1,000.

Item Number: 004
Description: MODULE. Transmission Control Module.
MODULE,TRANS CONT(W/O CALN)(ACDelco #24252114). Required: 01
For: N1 4-SPD A/TRANS(M30) (2008-2009) (2008 - 2009).
For: N1(06-43) 4-SPD A/TRANS(M30) (2010-2010) (2010 - 2010).
For: ST1 4-SPD A/TRANS(M30) (2008-2011) (2008 - 2011).
Cost: $91.55
Part Number: 24252114

rshadd

· #9 · Aug 19, 2013 (Edited)

FYI....
From the shop manual....

Transmission Control Module (TCM) Replacement

Procedure
A new TCM requires programming. Refer to Control Module References .

Tip
• Disconnect the TCM electrical connector.
• Twisting or tilting of the transmission control module electrical connector while disconnecting may result in bent or misaligned electrical terminal pins.
• It is recommended that transmission adaptive pressure (TAP) information be reset. Resetting the TAP values using a scan tool will erase all learned values in all cells. As a result, The engine control module (ECM), powertrain control module (PCM) or TCM will need to relearn TAP values. Transmission performance may be affected as new TAP values are learned. Reset the TAP values. Refer to Transmission Adaptive Functions.

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limequat

· #10 · Aug 19, 2013

alexisbarkl said:
No, nothing else has lost connection. I was told its not smart to buy a used one and that new ones are 1,000.

Was this the same person that tried to sell you a new one for $1000?

I've never had any problem with my TCM loaners - all used. I usually have to rewrite them to get Colorado specific code. If you get one from a 2009 Colorado, just disconnect battery, plug it in, go.

alexisbarkl

Discussion Starter · #11 · Aug 19, 2013

limequat said:
Was this the same person that tried to sell you a new one for $1000?

I've never had any problem with my TCM loaners - all used. I usually have to rewrite them to get Colorado specific code. If you get one from a 2009 Colorado, just disconnect battery, plug it in, go.

No, my dad told me it wouldn't be smart and said he looked up the new ones pricing and it was 1,000.

So you've had this problem a few times?

limequat

· #12 · Aug 19, 2013

alexisbarkl said:
No, my dad told me it wouldn't be smart and said he looked up the new ones pricing and it was 1,000.

So you've had this problem a few times?

Nope, NEVER had this problem. I sell mail order tunes and use used TCMs.

alexisbarkl

Discussion Starter · #13 · Aug 25, 2013

The truck is fixed, running and happy. But I did come across a lot of trouble with this problem not being able to find any answers online so I figured I would post the outcome for anyone who comes across this problem with their truck. The code the truck gave me was U0101, lost connection of transmission control module. At first the problem was something that would come and go as I was driving around the city. Before I replaced anything serious I wanted to see if it was something as simple as the battery, got the battery tested and the guy told me it came up as bad, so I bought a new battery and the previous battery was 4 years old and from the factory. After the first day of a new battery I started my truck and the problem was not only not gone but now it was permanent and on 24/7. No working speedometer, Odometer, gear lights, and the truck was in limp mode. The last thing I want to do is take the truck to a shop for someone else to fix. But the tcm is really something you can't replace yourself considering you have to have it reprogrammed by computers to fit your vehicle, unless you buy a used one that is from the same make,model and year as your vehicle. Ended up having to take it to the dealer and at first they couldn't figure out if it was just the tcm or the WHOLE transmission. It ended up just being that the tcm went bad and luckily my truck is still under the 5 year power train warranty so it was free. New tcm would have been $142.00 and $125.00 for installment. Thanks for all the help provided.

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rshadd

· #14 · Aug 26, 2013

Glad you got it fixed and that it was covered on warranty. Thanks for letting us know how the issue was resolved.

donavandudley

· #15 · 4 mo ago

limequat said:
Nope, NEVER had this problem. I sell mail order tunes and use used TCMs.

What kind of tunes you offer I’m interested

cart7881

· #16 · 2 mo ago

lewisrassel said:
You can get them used for very cheap and they do not need to be reprogrammed for your truck.

"You can get them used for very cheap and they do not need to be reprogrammed for your truck."

If you are referring to a TCM or a PCM(ECM), that is incorrect information.

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