AT Light illuminates / Gear switches to 3

[iraklic]

Hello,

I have 2006 Mazda3 GT. 120k Miles. About 3 weeks ago I was driving with about 40-45 mph and suddenly car jerked. I though I rolled over a rock or a branch but then I noticed an AT light illuminated for a split of a second. It went away and car continued normally.

This happened a couple more times that same day.

AT sometimes illuminates even when sitting on the red light.

I checked the ATF and the level was low.

Since then I have drained an ATF and cleaned the pan. Replaced the filter and refilled with Mazda ATF M5 (M-V). Now the level is right.

The problem did not go away!!!

I am guessing for some reason there is some kind of malfunction and that is why AT illuminates and then it switched to the safe 3rd gear. That is why it jerks. The AT does not stay on and my CEL is not on either. So I cannot pull any codes. I tried but it just says no codes.

The ATF that I drained was pretty dark. I did not do a flush but I am going to drain again and refill again. May be even replace a filter again. So I will bring it to a much cleaner condition. I can do drain and refill even once more to make sure the ATF is nice and red. This is an easy procedure and I don't mind it.

Any suggestions what else should I check? Can it be that my sensors are going bad? May be not quit bad yet? Any connection issues?

Do you think this can actually be the transmission going bad? The car drives nice and smooth otherwise. I tried to drive in manual and it can do that too.

Any suggestions are welcome.

 

[iraklic]

So 40 views and 0 answers? Nobody had come across similar problem or my post was too long and boring to read through?

 

[concept]

This guy bought a used TCM and that fixed his problem:

http://www.************.com/showthread.php?t=377889

 

[iraklic]

Could you please fix that link? Or just type the missing part for me. Thanks.

 

[concept]

For some reason, this website eliminated parts of the link. (probably because it came from a competing forum)
http://www.************.com/showthread.php?t=377889
I've repasted it, above.

First post:

Hi everybody, I come to this forum looking for advise on a current problem I have on my Mazda 3. Mine is a 2006, 2.3L engine with AT transmission with almost 120K miles on it. I used to get the engine CEL ON together with the AT light ON briefly and it went away by itself for a while. Whenever I got the warning lights ON I was not able to retrieve any codes from the computer, whenever I read it, I always get an "E" from it which I think means an error. I continued driving the car until a major electrical issue took place last week. I came from work as usual and left the car at home, the very next morning when I started it, I got a "Christmas Tree" on the panel, the engine CEL was ON along with the AT and Power Assisted lights and the power steering seemed slight stiff from normal. When the car was shifted into Reverse, it shifted very hard and when placed in D, the car barely moved, it was like in 3rd (no shift positions are displayed). It showed the same symptoms like the AT was in "fail fix" mode. I tried several things like disconnecting the battery for a while and re-starting the car and after a while it worked OK and the AT and Power Assisted lights went away but the CEL remained there. I went over the street and drove the car as usual without any major issues, except at one point that it did like a down shift by itself that scared the hell out of me since I was driving in the highway and this was something I was not prepared for. The AT light came ON briefly while this lasted and went OFF again. When I arrived home I switched the engine OFF and let it rest for a while, but when starting the engine again, same lights are ON again with the same condition on the engine.

Did some search in Google and found some persons with similar reports and indicated that a new PCM solved the issue. I am currently looking for a PCM, but so far without any luck. Am I in the right track or some one else think the problem is somewhere else?

Update - Did replace the Turbine Speed Sensor as seen on other posts here but problem remains the same. I start the engine and leave it for a while, all of the sudden the AT and Power Assisted lights go OFF, but the engine CEL keeps ON and will not read a code. Also noted that when the ignition switch is turned ON without starting the car, the engine CEL light flashes 7 times and then stay ON.

last post:

All:

Just wanted to provide an update on my car problem for the benefit of others that may have similar symptoms. The car is fixed, the culprit, the TCM. I have to correct my previous statements about the engine ECM having the TCM enclosed on it. The ECM has some controlling on the TCM, but the TCM is a unit of its own. It is located under the AT LH side mount under the battery tray and it is mounted on top of the AT with three bolts. It has a single connector similar to the two on the engine ECM, the unit looks like a motorcycle voltage regulator since it has some cooling fins on the top. Just make sure that when replacing it the battery is not connected.

My mistake cost me around $400.00 since I replaced the ECM + had to bring someone at home to reprogram it and after that the problem persisted. There is no way that you can change the ECM without having to re-program it, the vehicle security features will not allow it to start. The guy that programmed the ECM ran some other tests that helped us figure out the problem and after doing some research we found the TCM unit.

Luckily I was able to find an used TCM at a local tranny yard for $50.00 which fixed my car. If you go to Mazda, this part cost around $500.00.

 

[iraklic]

This may or may not be the same issue. I do not have CEL ON. I think this is a crucial difference. I will try to pull transmission codes if Autozone does it. Also I am going to remove the transmission solenoids and measure the resistances. By the way, anybody has a chart of the resistances for 2006 Mazda3 GT?

 

[iraklic]

OK, today I got the check engine light on. I will check codes tomorrow. But probably something was failing and it failed now. I only hope it is some kind of sensor...

 

[quigley2003]

It’s your TCM module. We had the same issue and I guess where the TCM is it heats up and burns out.