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Hi,
You guys repaired a tcm for me last week, for my 2008 Mazda 3. I had a CEL light, AT light, and TCS light all come on, with multiple codes and very rough shifting into reverse and drive. After some research I decided sending the tcm to you guys for repair would be the best option.
After receiving it back, I installed it and relocated it to the brake lines, as you recommend. With everything back together, I started the car and the CEL light and TCS light are now off, but the AT light remains on and the hard shifting problem remains. Before installing, I checked all the wiring and everything looked good...everything is clean, connections are secure. I checked the fuse for the tcm, and that is fine, also. I did try the trick of clamping the battery cable together off the battery for 40 minutes. That did not help either.
I am not sure what to do next. The fluid isn't brand new, but it isn't burnt or dirty either. We actually just bought this car and before the purchase we test drove it extensively and had it checked out by our trusted mechanic, with no issues other than needing brakes. It was shifting very smoothly through all gears for several miles, so I highly doubt it has anything to do with the fluid. There are no leaks and the fluid is full and clean. It wasn't until we tried to back it out of the garage the next day that everything went haywire with the 3 dash lights and hard shifting.
I went out and bought a scan tool, hoping it would give me some kind of readout on why the AT light is still on. The only code being thrown is for an O2 sensor. When I clear the codes, the AT light goes off for about 2 full seconds, then it pops right back on again.
Should I send it back to you guys for another look? My order number was 758318H. Thanks.
Topic starter
Posted : 03/30/2023 11:23 pm
Hi there, we're sorry to hear that you're still experiencing hard shifting issues. It sounds like you already performed all the troubleshooting steps we would recommend. Some of the level entry OBDII scan tools don't have the ability to communicate with the TCM only the ECU which is probably why you're not getting any codes.
The transmission fluid is always a good idea to service. Having a new filter and fluids can clear certain symptoms. If you were getting P0715 I would check if the speedo sensor is faulty as that can throw codes relating to the TCM as well. Ultimately, we will be sending you an RMA label via email so be on the lookout for that we'll try to help you resolve this issue if there is still a problem with the TCM as quickly as possible.
Posted : 03/31/2023 10:51 am
Serge - UpFix Team liked
Thank you, I received the email and the tcm is back in transit to you. I did not originally purchase the firmware update for $99; could that be part of the problem?
Topic starter
Posted : 04/01/2023 1:48 am
We'll double-check the firmware and if needed flash it to the latest version under warranty as well as inspect the circuit board itself and stress-test it for an extended period of time to see if we can replicate the same issues. You should've already received an RMA label. We'll be on the lookout for it and keep you up to date once it arrives.
Posted : 04/01/2023 1:57 am
Serge - UpFix Team liked
Hi Ernest,
I received back the tcm that you fixed under warranty. I still have an AT light on and hard shift into reverse. I should mention that while you were repairing the tcm this time, I went ahead and changed the trans fluid, filter, all 5 shift solenoids, and the epc sensor. The solenoids I used were reman'd oem parts. Then I installed the tcm when I got it back. I can't figure out what else could be causing the AT light and hard shift. Any further suggestions? Is it worth taking a third look at the tcm?
Topic starter
Posted : 05/01/2023 2:03 am
Hi John, we'll be sending you a replacement fully refurbished TCM with the same part number that should be plug-and-play. If it works out well, great let us know. If you're still having the same exact issue, then chances are there's something going on in your vehicle. We'll be sending it out 5/2 (today) to you at no extra charge. We hope to hear from you soon.
Posted : 05/02/2023 4:56 pm
Serge - UpFix Team liked