TCM Problem or not?

2006 CHEVROLET COBALT
165,000 MILES • 2.2L • 4 CYL • 2WD • AUTOMATIC
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DENNIS5601
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Engine light came on and showed power steering on digital screen under tachometer, odometer. When putting in gear it's rough and has a little jump when I start to go. Plus, the transmission will not come out of first gear. I replaced the TCM with a new one and a used one and the problem got worse. I was reading and noticed this is a common problem. Please can someone give me the answer to solve this problem? I'm hoping it's not a costly one.
Sep 23, 2022 at 9:05 PM
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JACOBANDNICKOLAS
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Hi,

By chance, have you checked to see if there are any diagnostic trouble codes stored? The idea that it got worse after a new TCM was installed leads me to believe the TCM isn't the issue.

Have you scanned the can-bus to see if there are codes stored? CAN stands for controller area network. Basically, the different modules/computers are tied together via a few wires. This type of scan will retrieve codes regardless of the module storing them.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know.

Take care,

Joe



Sep 23, 2022 at 11:00 PM
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DENNIS5601
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A friend of mine took the car to get the TCM programmed, he said his computer wouldn't communicate with the TCM. He did the trouble code test before and after he tried to program the TCM. Like many people who have had this problem, I know someone had it fixed and tell me what they did to fix it. I heard that you have to take it to a dealer to reprogram all the computers in the car. I know the dealer will cost 1k or more. Please help!
Sep 24, 2022 at 5:13 PM
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JACOBANDNICKOLAS
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Hi,

I wish I had a better answer, but often times that is the case. Different programming requires specialized equipment.

However, I have a question. When your friend tried to communicate with the TCM and was unable to, did he have a scan tool that can communicate with modules other than the engine control module? I ask because it should have at least communicated.

Let me know.

Joe

Sep 24, 2022 at 9:18 PM
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DENNIS5601
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Sorry I was so long, busy. I talked to my friend about it. He said that he did program the TCM but thinks it's a wire that is bad going to the TCM. He will be checking on the wires at TCM soon and I will let you know something. I will let you know, and the form know how the problem was solved. Dennis
Sep 28, 2022 at 7:29 PM
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JACOBANDNICKOLAS
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Hi,

Thank you for letting me know. I am interested in knowing how things are going.

Take care,

Joe
Sep 29, 2022 at 5:57 PM
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DENNIS5601
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Problem solved! My mechanic told me to take a picture of my TCM and get the exact part number. I went to eBay again and ordered another TCM from them with the exact tmc number. Wow, my mechanic plugged it in, he also plugged his meter in and took it for a ride. He came back and bam! It worked. Ps, i had to try four TCM's, two that needed flashing and two that didn't to find one that worked with my car. Dennis.
Oct 16, 2022 at 4:23 PM
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JACOBANDNICKOLAS
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Hi,

Thanks for the update. I'm glad to know the problem is resolved. Also, this explains why there was no communication with the TCM. Ugh!!!

Regardless, thanks for letting me know. Your post will likely help others in the future.

Take care and feel free to come back any time in the future.

Joe
Oct 16, 2022 at 8:47 PM