07 SS 2.4, U0101 Code, No Speedometer, Power Steering, Abs - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
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post #1 of 2 (permalink) Old 07-06-2019, 09:19 PM Thread Starter
pacamaroman's Avatar
Join Date: Jul 2019
Location: Spring Grove, PA
Posts: 2
07 SS 2.4, U0101 Code, No Speedometer, Power Steering, Abs

Hi Everyone!! First time poster here. I bought a 2007 Cobalt SS 2.4 Automatic that had a bad timing chain. I put a new timing chain in and the motor runs great, but I have a U0101 code (Lost comm with TCM) and power steering, traction control starts flashing on the display and the ABS light comes on. It comes back on as soon as I clear it. I have been researching for many hours through before I became a member, and have tried all of the remedies that I have came across, but none have worked for me. I am totally stumped and hoping someone can point me in the right direction and help me!! Thank you all in advance!! I have done the following:
Cleaned the following grounds: main one in trunk, one under headlight, one under cooling tank, one under washer fluid resevior, one on firewall, one on trans stud, one under driver seat, one on block near ac accessory.
I added a ground to the TCM, and I tied a few of the other grounds together with ground straps.
I tried 2 different batteries that were almost new, had one load tested at Autozone and tested good.
I swapped in another alternator.
I cleaned all of the positive connections on alternator, starter, and battery.
I replaced the ECM/TCm fuse in BCM and ECM fuse in the underhood box with brand new fuses, although the old ones looked good.
I removed and reseated the 2 BCM connectors over a dozen times and the tcm and ecm about 5 or 6 times.
I hooked up my OBD2 scanner to it and it showed 0 mph on the scanner, even though I was doing about 20. So I changed the VSS sensor, and yielded the same results. I put the car up on jackstands, and had my wife put in gear and let the front wheels spin. I took my voltmeter and set to AC current, and as the wheels spun, I checked and verified that the current increased on the voltmeter, but for some reason doesnt register on the speedometer.
I have examined almost all the wires, I removed 90% of the conduit that hides the wires and see no rubbed or broke wires.
I swapped in another TCM from the salvage yard (wasnt programmed to my vin but was told thats ok for testing purposes), and that did nothing.
I can communicate with the all of the modules except the TCM.

Im totally lost, any help is greatly appreciated!! Thanks a lot guys!!
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post #2 of 2 (permalink) Old 07-08-2019, 07:51 PM Thread Starter
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Join Date: Jul 2019
Location: Spring Grove, PA
Posts: 2
BTW, I forgot to mention in my original post. I did go through all of the fuses in both locations and made sure they were all in good shape. And also, I swapped around the relays around, still had the same issue.
Thanks in advance for any help!!
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lost comm to the tcm

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