2012 Mazda5 Touring with Shifting Problems

[Tony117]

What's good everyone. I have a 2012 Mazda 5, well my wife does. It use to be her daily driver. She loves this vehicle. Well about a 2 years ago we started having transmission problems with it. Shifting and everything. Now I'm a believer that if i don't have to take it to a mechanic i will not, main reason being i love working with my hands and get a great satisfaction when i fix something and im retired so it gives me something to do. So about 2 years ago we started having problems so i did some research and it seems as if i had a bad tcu. I sent it off had it looked at they said it had some bad things like capacitacors and what ever and had it fixed. Or so i thought. Long story short ended up getting my money back since it did not fix the problem. So i got a lil frustrated and by then we had gotten the wife another vehicle. So we put this on the back burner. Now we are trying to get it back on the road as my oldest one is starting to drive. So my wife wants her car back and give my daughter the car she is driving one of the main reason the Mazda has a whole lot more get up and go than what she is driving and i will not say what kind. If i did i may get kicked off the forum and i just got here. Well i got another TCU from a wrecked vehicle and it was working great on the wrecked vehicle, but when i installed it into my vehicle i had the same exact problems as the one that i had in it before. Has anyone else had this type of problem. I have some codes u0101 lost communication with tcu, p0451 evaporative emission system pressure sensor/switch range performance, p0757, shift solenoid b stuck on. I also replace every solenoid in the transmission. Now i have a code reader and i have cleared the codes and they come right back. I also ran the codes with out the tcu connected it came up with the same code except the on p0757 shift solenoid stuck on. Anyone else came across anything like this. I wanted to ask before i drop money on a ECM. Which is my next move. Oh the vehicle only has 128879 miles. by todays standards that is practically brand used. Also will not go into reverse. I have to flintstone it to get it out the yard.

 

[negusm]

Pretty sure your transmission has issues...especially if it won't reverse. I really doubt an ECM is going to fix anything.

One thing you could work at is to get the wiring diagram for your car and focus on the P0757 code. I would check all grounds and power wires throughout the car as well as the TCM.

You might want to grab the transmission from the wrecked vehicle if the mileage is low. With 130k miles, your transmission may be near the end of its life. They were not engineered to go much past 150k.

 

[Philby]

What's good everyone. I have a 2012 Mazda 5, well my wife does. It use to be her daily driver. She loves this vehicle. Well about a 2 years ago we started having transmission problems with it. Shifting and everything. Now I'm a believer that if i don't have to take it to a mechanic i will not, main reason being i love working with my hands and get a great satisfaction when i fix something and im retired so it gives me something to do. So about 2 years ago we started having problems so i did some research and it seems as if i had a bad tcu. I sent it off had it looked at they said it had some bad things like capacitacors and what ever and had it fixed. Or so i thought. Long story short ended up getting my money back since it did not fix the problem. So i got a lil frustrated and by then we had gotten the wife another vehicle. So we put this on the back burner. Now we are trying to get it back on the road as my oldest one is starting to drive. So my wife wants her car back and give my daughter the car she is driving one of the main reason the Mazda has a whole lot more get up and go than what she is driving and i will not say what kind. If i did i may get kicked off the forum and i just got here. Well i got another TCU from a wrecked vehicle and it was working great on the wrecked vehicle, but when i installed it into my vehicle i had the same exact problems as the one that i had in it before. Has anyone else had this type of problem. I have some codes u0101 lost communication with tcu, p0451 evaporative emission system pressure sensor/switch range performance, p0757, shift solenoid b stuck on. I also replace every solenoid in the transmission. Now i have a code reader and i have cleared the codes and they come right back. I also ran the codes with out the tcu connected it came up with the same code except the on p0757 shift solenoid stuck on. Anyone else came across anything like this. I wanted to ask before i drop money on a ECM. Which is my next move. Oh the vehicle only has 128879 miles. by todays standards that is practically brand used. Also will not go into reverse. I have to flintstone it to get it out the yard.

The tcm is not a plug and play part. It is also known to fail, Look into an electrical company called UpFix. They explain it perfectly,

 

[Snorting2.5]

You might want to grab the transmission from the wrecked vehicle if the mileage is low.

No.

With 130k miles, your transmission may be near the end of its life. They were not engineered to go much past 150k.

Then why is it that my nearly 200k mile 6 speed auto shifts smooth as if it is ready to double its mileage? I had the transmission filter and fluid changed regularly. If OP did the same, it likely would not have happened.

OP, since i'm sure your pan was never dropped before you started having issues, I think it is the valve body. Replacing the solenoids certainly wouldn't hurt, but I strongly advise you to take the car straight to a transmission specialty shop and have them figure out what's going on.

 

[Silentnoise713]

Then why is it that my nearly 200k mile 6 speed auto shifts smooth as if it is ready to double its mileage?

You are comparing apples to oranges and using anecdotal input.

-Mz5 never came in 6sp auto, not sure what year/make/model you are driving.
-It uses a Forzda era 5sp trans, suited for Mz3/Focus, not Mz5 extra hefty weight.
-Not all trans are designed with equal quality.
Gears Magazine - Shifting Our Focus Back on the FNR5 there also a YouTube tech who tear down the FNR5 and call out some issues.
-No trans last forever with simple fluid/filter change.
-Don’t compare mileage. How the car was used is most important. A lot of short distance (before tans fluid get to temp, constant 1-2-3 shifts, P-N-R, engaging torque converter at at stop light on hot days, etc.) errands runs will wear it out much sooner than driving 100k miles highway (stays in top gear AND you get constant air cooling).

 

[Tony117]

The tcm is not a plug and play part. It is also known to fail, Look into an electrical company called UpFix. They explain it perfectly,

From everything I researched, and actually sent the first one off to be fixed may have been to the company upfix it has been 2 years. They said nothing about it not being plug and play they did not ask for Vin millage or anything. I will research more. It was explained to me that the tcu was plug and play but the ecu was not.