(Crossposting this from another Mazda forums to increase visibility...)

A couple of days ago, my 2012 Mazda 3 (with ~120K miles) began kicking whenever I started accelerating out of a complete stop. When I take my foot off the brake and begin to depress the accelerator, the car briefly (2-3 seconds) acts like it's in neutral or park, before slamming into 1st gear and jumping forward. often with a little skid / peel out to go with it. Once I'm moving, the automatic shifting is fine, but the problem returns the moment I come to a full stop.

When I throw the car into its "quasi-manual" mode, I don't have any problems. I can drive in automatic, stop, throw the car into manual, accelerate out of the stop just fine, and then switch back over to AT.

When I put the car into reverse and then into drive, the car "sticks" in neutral / park for closer to 5 seconds, regardless of whether I shift into automatic or neutral.

My Check Engine and AT lights are NOT on.

I quickly learned that these behaviors sound a lot like what happens when the TCM starts failing, and that TCM failure is quite common among this vintage / mileage of Mazda.

With that in mind, I went to an AutoZone this morning and had pull codes. The car put out four codes:

• U3003-16: Battery Voltage - Circuit Voltage Below Threshold
• U0452-86: Invalid Data Received From Restraints Control Module - Signal Invalid
• U0140-00: Lost Communication With Body Control Module
• U0428-62: Invalid Data Received From (SASM) - Signal Compare Failure

Obviously none of these are directly tied to the TCM, but they ARE all related to the car's electronic communications network, and I would imagine a system with a faulty TCM plugged into it MIGHT create some downstream problems along these lines. (I don't know that for a fact, though.)

The Battery Voltage code prompted me to have AutoZone check the battery and alternator. They said both looked fine.

I do know that I'm overdue for a serpentine belt replacement. Otherwise, the car is in pretty good shape and has given me few problems.

I may be wrong, but I don't believe the car has ever had a full transmission service, and I have not yet checked the dipstick to see what my fluid levels and color are like. (It's my understanding that this is technically a "sealed" system, but I don't know whether that means much once the car reaches this age.)

The local transmission shop isn't interested in getting into the electronic side of things and directed me to the local Mazda dealership. The dealership is willing to run a diagnostic eval for $165 next week, but I'm not sure whether they'd give me any info I don't already have. (I have not had great experience with them in the past.)

Any advice on next steps? Does this all still point to a likely TCM problem, and if so, should I just start looking at reliable refurbishers to either get this one fixed or exchanged? Are there possiblities I'm not considering? Do those codes point to something entirely different?

Thanks for your help!

 

Welcome to the forum

You have information overload and not the important first basic information. Also, the DTC you had retrieved are too old. They are also incomplete. If done correctly there would have been DTCs in permanent file at least and that is why your check engine light had not yet been activated. Whatever the condition it seems to indicate correcting and then repeating dure engine cycles to they are in the permanent file area. They are also slowly collecting on your counters. I would recommend to go to Mazda at this point. If you do throw in the towel (better advise) find a service shop that has a certified Automotive Diagnostic technician and pay the 1 hour fee to give you the correct information what is the problem if TCM or ECU/PCMM related and then you can at that point decide if you have the DIY skills to take it from there and service the problem with your Mazda

I do get that you are trying but you side stepped diagnostic steps and possible problem illuminations

 

I'll find some more if you'll point me in their direction. Clearly you frequent them all.

 

Yup pretty much belong to all of them.

I will tell you before anyone can help you the first thing you must have is a ECU scanning tool and not rely on traveling to an auto parts store to get your ECU scanned. By that time, you can and those that do often collect more trouble codes then the original one making helping a member like you very difficult.

Look dude you information is well written just technically BAD. You did so many wrong things and if you end up going to a service shop don't show them what you did. LOL
If you came into the shop with that first post I would say thank you and it would go behind the service write up only to be filed later. LOL

Oh I did read that! response on the other place and maybe you should take that member starting diagnostic advise about your battery ? Then come back here and stay on this forum for a while and a couple of us I am sure will help you?

 

Hey,
Whenever i have had "weird" electrical issues the first thing I do is find , check, clean or replace all chassis and engine grounds.
Look for mice damage, check electrical connectors. In this case connectors on the transmission.

Do recall from about ten years ago there being a internal speed sensor in the auto tranny that caused similar issues that you are describing.

Good luck.

Pete

 

Wild Goose chase...
Except that does not cause all these at one time:

Quotejaskins post #1: With that in mind, I went to an AutoZone this morning and had pull codes. The car put out four codes:

• U3003-16: Battery Voltage - Circuit Voltage Below Threshold
• U0452-86: Invalid Data Received From Restraints Control Module - Signal Invalid
• U0140-00: Lost Communication With Body Control Module
• U0428-62: Invalid Data Received From (SASM) - Signal Compare Failure