AT light on Mazda 3

Pull the codes before you clear them.

Both times the AT light disappeared after turning off engine. So I would have to go directly to a code reader while the motor is still running. The mechanic picked up nothing yesterday as the motor was already off . I already disconnected negative battery terminal and everything is fine now. Also, tranny fluid is pinkish red and at correct level. From what I've read and analyzed here and on other forums, I'm in better shape than a lot of others with tranny issues. Mine is likely or hopefully something electrical rather than mechanical. Another thing I'm trying to do is to keep it in Auto D and not use the M so much. It's better to wear brakes than potentially damage tranny.

Hey there, did you ever figure it out? My 2007 Mazda3 has started doing the same thing.

NO. It has been a problem for 10 months on and off. It hasn't gotten worse so I have learned to live with it.

Hey; the problem mentioned has just started on my car; what is the suggestions of you?

Check your input and output speed sensors. Mine was doing the same thing and that was my issue.

I bought a cheap input speed sensor 6 months ago but never installed it. Car still does same thing, but it goes away for a month if replace a quart of dirty fluid and add a clean qt. This is easier to do than fool with the input sensor. Next time I'm going to add some Lubegard additive. Universal type # 60902. I suspect that my problem is a solenoid valve that gets stuck. Once car is warmed up, metal expands in valve and it works fine. Fresh fluids help this.

Similar problem. 2007 Automatic Mazda3 Hatchback 2.3L Driving to work one day and suddenly car jerks and shifts down from 5th to 3rd. Yellow AT light is on and car will not shift up from 3rd, runs at high rpms. Pull over and shut off car. Start back up and problem goes away... until I’m driving home. Same symptoms. This happens for days. First fix I try is replacing tranny fluid and filter. No change as problem happens again next day. Next fix is I replace the speed sensor that’s located on top of the tranny (under the air filter tray). Easy to fix. Car worked fine for 2 weeks (~600 miles). Today, after picking up lunch, same problem occurs. AT light is on and won’t shift above 3rd. The next fix I’m going to try is the TCM (Trasmission Control Module). It’s definitely pricier ($600) but still cheaper than a new car or even a new tranny.

If your Mazda 3 shifts gears from 5 to 3 randomly, the AT light comes on flashing with the engine light, then the AT light goes off in about 3 miles, followed by the engine light in about 30 like everything is fine, it's very likely the Transmission Control Module. The TCMs on Mazdas 3s are pron to overheating due to their proximity to the engine and crap out after 40k miles or so.

I must have been really lucky because mine didn’t crap out until 166k miles. But I have heard, in other forums, this happening when the car is still new (<30k miles). Apparently they’ve gone thru 5 versions of the TCM as the latest has a part number that ends in ‘E’ where the previous started with ‘A’ and went thru the letters until ‘E’. For those wondering, the latest as of January 25th, 2019, the part number for a TCM for 2007 Automatic Mazda3 2.3L is L34T-18-9E1E.

I had check this problem for my custom by scancar and i found a foult... On 3 and 4 gear ...

At means automatic transmission. Add tranny fluid. Mine did the same, shifting hard, resets when shut off. The plug to add is under the air box and more less under the battery box.

i have the same problem with my 05 mazda 3i sedan . FIrst i noticed the acceleration from stop was way slow than the car started shifting way to late than jerking than the At light popped up and 2 weeks later my car wont even make it up the driveway. i have not had much time in the last week to take the time to look at it more . sounds like you guys are all having a problem pretty close to mine any help would be great . thanks guys !

I have same problem my top tronic don't work as well a nd it stays on 3rd gear

Don't laugh ... Have you tried spraying off your radiator with a high pressure sprayer? If it gets clogged up with bugs and whatnot, from alot of freeway travel, it is a great possibility! It will clog up the tranny's cooling system....

my 2003 mazda 3 2.ol bogs and the lighy flickers when going 100km and i got a code p0706 tr switch it has a new transmission range switch does any body know what the cause is

Just bought a 2010 Mazda 3, 2.5 L sedan with 73,000 miles. Thought all was well. 2 weeks later the AT light came on and transmission was intermittently jerking/ faultering. Took to Mazda dealer- they replaced the TCM (Transmission Control Module) which they said was under warranty. I suggest taking it in. They said if you drive around for a while in denial it does permanent transmission damage and you're buying a big repair. Flush the trans every 30,000 miles.

Check the Transmission control module!! That's what was wrong with mine! Mine would be good in 1st skip 2nd and 3rd and be fine in 4th and 5th! I checked Around everywhere and the parts pretty expensive! But thank God I found one at a pretty decent price!

Update to my previous comments. I had the issue of the trans getting stuck in 3rd. I changes fluid, replaced sensors, still had the problem. The issue was the TCM. Changed it almost about 8 months ago and haven’t had the problem since. It’s pricey but it’s worth it!

I want to know where is locate the tcm on a mazda 3 2005

I have a 2007 Mazda 3 2.3, my AT light came on suddenly and (when using manual drive) the gear shift numbers disappeared, and (when in automatic) I am unable to shift above 3rd gear. It goes on and off, with no certain pattern or rhythm. I stopped by Autozone to have the codes scanned and it came back as P0753, which is for the Shift Silenoid A. I'm no repair mechanic so I finally gave in and called a highly recommended transmission mechanic who agreed to diagnose my car and tell me what's wrong. He said he recommended a TCM (Transmission Control Module) replacement and said the part itself would be pricey but that I could most likely install it myself. I assured him that I was incapable of even attempting any vehicle repair, as I'm the type who duct taped a hole in my coolant reservoir when it developed a hairline crack. He insisted I try as it would be stupid to pay a ridiculous shop fee for labor of repair that only takes 5-10 minutes to install. I'll have to update how that goes once I receive the part (which is fairly difficult being I really hate paying dealership/corporate auto store prices, and cannot find them at all on Rock Auto, Parts Geek etc. (Any advice there would be appreciated!) I just wanted to share my experience as absolutely no codes or research of my own came back to TCM error. Apparently, even though the code came back as a Shift Silenoid A error- according to the mechanic, it is rare that a simple solenoid fixes transmission issues once the AT light comes on.‍♀️

Davis, I'm pretty sure the TCM is under the battery housing. I no longer have my Mazda, but I did study this problem a little. The battery comes out, then the plastic battery housing comes out and it is then accessible. I also think some electrical terminals have to be disconnected. But google or you tube this first to get a better idea.

My 2008 Mazda 3 2.3L model has the similar problem. The Engine check and AT on, manual transmission not working, automatic only shift to 3 rd gear. Very shaking when shifting from parking to rear or drive. After all research and recommendation, I changed TCM yesterday, It didn't work. Does anyone have any suggestion? Thanks!

Guru9DSD7V My 2008 Mazda3 2.3L just did the same thing. I'll follow up if I figure it out.

Guru9DSD7V, try replacing the speed sensor. When I had that problem, that was one of the things I tried before replacing the TCM and it fixed the issue for a few weeks. So if replacing the TCM w the latest version didn’t work for you, that might.

I had the same issue as David with the same error code. In my case there was a short circuit inside the tcm that was blowing up the fuse and started smoking. At first mechanic thought it was the selonoid valve and dirty transmission so he replaced the fluid/filter etc with no luck. The oem part costs 750$ Canadian so it’s not worth it. I recommend go hunt for a tcm module at a scrapyard, that’s where I got mine for 50$. Make sure the letter and serial matches the spare. From what I saw the repair is fairly easy, I would have done it my self if I knew. So far the car is shifting ok, hopefully it stays like this. Good luck

Pin connector on the tcm is a pin not making a connection to tmc

My 2008 Mazda 3 2.3L model has a similar problem. The Engine check and AT on, manual transmission not working, automatic only shift to 3 rd gear. Very shaking when shifting from parking to rear or drive. After all the research and recommendation, I changed TCM yesterday, It didn't work. Does anyone have any suggestions? Thanks! Update from the above message. So I tried to check the speed sensors as suggested by other customers. It did not work. I brought my car to " Mr. Tansmission" to get it checked. The staff was very helpful, they suggested I chanted the: electric circuits, and a used transmission>. total will cost about $2000 dollars. I was willing to accept the deal, but hold on ..... I checked the car files, my wife just had the transmission changed at the Mazda dealer one year ago.??? I decided to get it a shot. I went back to the dealer the next day. It turned out the transmission fluid was overfilled. I have been driving it for 10 days now, only the engine light still on, otherwise everything else is working fine for now.

If you are having TCM issues the best thing to do is remove it. Mazda mounted it to the top of the transmission so it breaks down from the heat of the transmission . Sent mine to myairbags.com to repair. It was $200.00 and it only took a few days to get it back.

Mine has been doing the same. I got new fluid and it worked fine for about a week. Then it started doing it again and i got a new tranny. Fine for 2 days and started again. What should i do next?

GuruQFX31. If changing out the tranny didn’t do it, it is probably the TCM (Transmission Control Module). I changed mine out and that fixed it. Been working steady for years since the change.

So I did replace my TCM (from Airbags.com/ UpFixIt). I purchased one of their already remanufactured parts, then sent mine back in for the rebate cost. The AT light came back on about two months later, and when I pull the code it says "No codes" for AT light. I've tried the hard reset, still not sure if I did it right, yet it drives fine with the light on. I have a warranty on the part until September 2021, so I figured I would ride it out until then and if the AT light gives me trouble before then I will just send it in to claim warranty. I did however discover my Engine light, that was coming on in sequence with the AT light, happens to be an EVAP (small leak). I have yet to find a mechanic, so I'm currently riding that problem out.

Another question, while I've "got y'all here" Does anyone know the diagnosis for the Exclamation Point Light. I know it will blink yellow when the tire pressure is low, but what about when it blinks and then remains solid yellow?

wow i can see that most of you didn't read the car user manual cause it says that happens when your trans temp get high so the at light goes on and the steptronic stops to ensure that the trans temp doesnt get even higher

Can anybody tell me where the tcm is if it isn't under the battery box I'm at a complete Holt trying to find this tcm I have a mazda 3 sp23 4 speed auto 2005 bk series 1 sadan I honestly can not find it

Mine was a 2007 Mazda 2.3L but mine was under some sort of guard under the battery. It was a metal bracket with a rectangular chunk of metal as the main shield. If you see something like that, you may want to remove it or check under it.