P0473 - Shift Solenoid A Electrical ( CEL & AT light) with limp mode and harsh shifts

P0473 - Shift Solenoid A Electrical ( CEL & AT light) with limp mode and harsh shifts

We have a 2008 Mazda 3, 5 speed auto. Last Tuesday my Fiance` left to go to work. She crossed a set of rail road tracks at 25-30mph and as soon as she got over them the car shifted hard and the "CEL" and "AT" light came on. She pulled over and called me. I looked everything over and couldn't find any loose connections or shorts. At first I figured it was a vehicle speed sensor but, after doing some homework on the symptoms I had the local autoparts store look up the error code.

P0753 - Shift Solenoid A Electrical

Since I am not that familiar with Mazdas I started doing some home work on the error code. From what i have read this is an electrical issues between the TCM and the solenoid A. So, I had to wait until Saturday morning to work on it. I pulled the air box and battery tray out to look at the wiring harness closer. I couldn't find anything obviously wrong. Since I was working in my parking lot I couldn't hear to test the solenoid in the car.

I have reset the check engine light several times and had to have her keep driving it to work (in limp mode) which is across town at slow speeds. She said that sometimes the AT light will not come on and the car will shift normally. Other times it will come on and stay in limp mode. I reset the CEL one last time and took it for a test drive. I made it about 10 miles starting and stopping before the AT light came on. Once it came on, it would stay on for me.

From what I can tell the TCM is most likely the problem. But, I know that her transmission fluid is due for a change. So, I parked her car and let her drive my truck (gah)

I ordered a new TCM from a module re-builder in California. It should hopefully be here this week. I also ordered a filter,gasket, and solenoid A & B kit off of ebay. My plan is to once I am off of work on Thursday to drain her flush her transmission, put in a fresh filter, and to bench test the solenoids according to the FSM procedure. (I am sorry guys I have damaged hearing so I don't know that I could hear the solenoid work in the car). That way if she does in deed have a stuck solenoid I can go ahead and swap it out. The solenoids are accessible by just dropping the pan right?

What transmission fluid do you guys prefer? I have seen the posts on how to flush this transmission where they used the Mobil 1 fluid. I was thinking of picking it up to run it but, I figured I would verify what to use. Seems like this transmission is very particular to what fluid is used. I stopped by W*lmart last night to see if they had any and found their Supertech that SAYS it is good for all Mazda transmission but, I am not too confident in it after some of the posts that I have read.

This whole project has kind of got me nervous... not just because she has my truck either!(boom04)

Anyone?

I found out that my TCM will be delivered today.

I am leaning towards going with the Amsoil signature fluid... I was thinking of flushing it with the Supertech stuff shown above.

How many miles are on the odometer? How long since the last change? What color is the fluid? The fluid type is the most important criteria. Whatever type is specified in the owner's manual is what you should use. Synthetic should be okay as long as it qualifies as the same type.
Sometimes, solenoids will not function properly if fluid level is low. This was an issue with my old MX6 GT, a while back. It's auto trans had 150,000 miles on it, yet was perfect again after I added some fluid. I would drain and fill it every 2 years (for 17 years) but it developed a leak that slowly reduced the fluid level.
By the way, a mechanic's stethoscope comes in handy when trying to pinpoint noises. I bought one from Harbor Freight for less than $20.

Thanks for the reply. We ordered a rebuilt TCM from a module rebuilder in California last Saturday. We got it in on Wednesday and I installed it on Thursday. Because of the weather I have not been able to flush the transmission or check the solenoids. However, this seems to have fixed the problem so far. I am planning on flushing the transmission in a couple of weeks and change the motor mounts while I am at it.

I will keep you guys posted if the issue comes back. But, I am hoping that was it because (with the holidays) we have driven the car about 215 miles since I swapped the TCM on Thursday and SO FAR the issue has been resolved.

hopefully my car would be fixed by replacing the TCM. it's quite expensive at the moment.

I hope that fixed it.
Thanks for the thread. I'm having the same CEL.
Updates?

Edit- you're error code was 0753. The title to the thread is wrong.

Brute what are you using to get your engine codes? Display looks nice.

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