transmission AT LIGHT ON SOMETIMES

[Pickeringuy]

Can anyone help? I have a 2004 Mazda 3 2.3. . The AT light comes on most of the time, the car still shifts through all the gears but very harsh. when the AT light is off ,the transmission shifts perfectly including the triptronic mode. I have done tranny flush, changed speed sensor on top of transmission , changed all three solenoids inside of transmission, even had Mazda try a re-flash, but still the same problem. Any help would be appreciated.

[ottoyu34]

Sound like 74sickness issue before. Any input?

[Cudgel]

Sounds like you might need a new TCM (transmission control module).

Did you pull up any codes?

[74sickness]

When does the AT light come on? If it is right when you get in the car and then it shuts off and shifts fine then it us your tcm. If it comes on after fluids warm up and won't go past 3rd gear then it's your transmission. Good luck if you have any questions ask me I had my transmission out 5 times until I fixed it.

[Pickeringuy]

When does the AT light come on? If it is right when you get in the car and then it shuts off and shifts fine then it us your tcm. If it comes on after fluids warm up and won't go past 3rd gear then it's your transmission. Good luck if you have any questions ask me I had my transmission out 5 times until I fixed it.

the light is not usually on when i get in the car. it will just randomly come on. The transmission while driving shifts through all gears no problem, just a little harsher when the AT light is on.Is the tcm separate from the ecm? I dont have a code reader that can read transmission codes, (I only have enova obd reader) any suggestions? thanks...

[74sickness]

the light is not usually on when i get in the car. it will just randomly come on. The transmission while driving shifts through all gears no problem, just a little harsher when the AT light is on.Is the tcm separate from the ecm? I dont have a code reader that can read transmission codes, (I only have enova obd reader) any suggestions? thanks...
Sounds like your tcm is shot, and the tcm is not part of the ecu it's on top of the transmission and the tcm could be bought on Kijiji for around 300. Make sure if you do buy a tcm that it is for a gen 1 because I tried a gen 2 tcm on my car and it did not work. If that isn't your issue then you could sell the tcm for what you paid for it. I would then suggest getting a new transmission if none of that works but I believe your tcm will be the issue. Let me know and send me the link when you find the tcm you are going to buy. Good luck

[microtandme]

Sounds like your tcm is shot, and the tcm is not part of the ecu it's on top of the transmission and the tcm could be bought on Kijiji for around 300. Make sure if you do buy a tcm that it is for a gen 1 because I tried a gen 2 tcm on my car and it did not work. If that isn't your issue then you could sell the tcm for what you paid for it. I would then suggest getting a new transmission if none of that works but I believe your tcm will be the issue. Let me know and send me the link when you find the tcm you are going to buy. Good luck

I've had a lot of trouble with my transmission even after getting a new one. Now when you say "when you get in the car and then it shuts off" do you mean when you turn the car on and the light shows then quickly shuts off? Because I can't remember if it showed before all these problems. Also it's not shifting good ever it's still under warranty but whatever you guys do don't buy from bodyline in Hamilton they ****ed me 3 transmissions and tried to blame it on the installers.

[Booter22]

Can anyone help? I have a 2004 Mazda 3 2.3. . The AT light comes on most of the time, the car still shifts through all the gears but very harsh. when the AT light is off ,the transmission shifts perfectly including the triptronic mode. I have done tranny flush, changed speed sensor on top of transmission , changed all three solenoids inside of transmission, even had Mazda try a re-flash, but still the same problem. Any help would be appreciated.

get this buggy into mazda asap. the longer you drive it the worse it will be. it either needs a flush, sensor ( which you have said you have done.) or full rebuild / replacement. but believe me the long you go the more its going to cost. so even get looking for a wrecker tranny. so id get looking for a replacement tranny.

[74sickness]

I've had a lot of trouble with my transmission even after getting a new one. Now when you say "when you get in the car and then it shuts off" do you mean when you turn the car on and the light shows then quickly shuts off? Because I can't remember if it showed before all these problems. Also it's not shifting good ever it's still under warranty but whatever you guys do don't buy from bodyline in Hamilton they ****ed me 3 transmissions and tried to blame it on the installers.

When you turn the car on the AT light will come on every time, but what im saying is when you start driving for a while and the light is on right when you get in the car and then the light shuts off after a couple minutes of driving, that usually means its your tcm from the research i have done and it has been quite a bit. What issues are you having?

[microtandme]

When you turn the car on the AT light will come on every time, but what im saying is when you start driving for a while and the light is on right when you get in the car and then the light shuts off after a couple minutes of driving, that usually means its your tcm from the research i have done and it has been quite a bit. What issues are you having?

Hard shifts until it's warm and Rpms will make it like high Rpms it'll shift hard some days and someways it'll be smooth

[74sickness]

Hard shifts until it's warm and Rpms will make it like high Rpms it'll shift hard some days and someways it'll be smooth
Have you tried changing your tcm? Mazda 3s are known to have tcm issues

[microtandme]

Have you tried changing your tcm? Mazda 3s are known to have tcm issues

Yes 3 times the most recent time was good but then a few weeks later it started shifting hard again

[74sickness]

Yes 3 times the most recent time was good but then a few weeks later it started shifting hard again
Are your running mazda mv transmission fluid because I know Mazda's are picky when it comes to transmission fluid.

[microtandme]

Are your running mazda mv transmission fluid because I know Mazda's are picky when it comes to transmission fluid.

Most likely not

[74sickness]

Most likely not
The people at part source won't let me buy transmission fluid from them because it causes too many issues, try mazda mv it's actually cheaper then the stuff from part source if you get the tm3 discount

[microtandme]

The people at part source won't let me buy transmission fluid from them because it causes too many issues, try mazda mv it's actually cheaper then the stuff from part source if you get the tm3 discount

Okay I'll have to try this!

[Superchargedx]

The 2004 Mazda 3 was very common for a hard 1-2 shift shock in colder weather.... This was resolved by PCM update.
I have never personally replaced a TCM on an 04 Mazda3 so I almost kinda doubt that is the issue, but who knows?
Is there/was there any codes in the system?
I agree either the ATF is very wrong or tranny is cooked😢😢