TSB 01-001/26 Coolant Control Valve PCM Code

[MrViking]

I had my 2022 CX-5 Premium repaired on 1/31/26 under the extended warranty defined by TSB 01-001/26. One of the things they do is to update the PCM with the latest software. My PCM version was/is PX2G-188K2-K. This revision lets the PCM know that my CCV no longer has the fail-safe thermostat in it, but the dummy plug. Cooling is now managed entirely by the fans and the Active Grill Shutters (AGS). For those who may not know, like me until after this repair, the CX-5 has shutters that cover the lower part of the radiator that open and close as part of the cooling system.

It's been cold here (for SE Virginia anyway) and I noticed that with temps in the mid-20s, the coolant temp had pretty significant swings between about 182° and 204° F. This is apparently the result of the "K" software rev. where the AGS don't open and close properly to maintain a consistent temp when it's cold. They open for too long and then close for too long. The same thing didn't happen when the temps were in the 50s. The coolant temp was a solid 195°-197°. Some research revealed that there are a couple more PCM updates. Namely revs L and M. M specifically addresses the AGS duty cycle. It changed from "open based on engine load" to "closed until 205° F" when ambient temps are below 32° F. Seems like this is exactly the fix I needed.

I took the car back to the dealer and asked them to check on it and after checking it, told me that it had the latest rev of the PCM software, which was the "K" rev. I'm pretty sure that they are not lying to me and when they connect the car and check for the update, it's telling them that no updates are available.

My question: Does anyone here who has had the CCV fixed with the dummy plug have a PCM rev later than "K"? An OBDII scanner would show the CID as PYUB012 or higher if the updated software is installed. My CID is PYUB011. Apparently the 011, 012 or 013 translates the K, L or M code letter on the PMC since 11=K, 12=L and 13=M

My wife, who has the identical year and model as mine, has the same CID as I do and it has not been updated so it's left me a bit confused. I'm told by AI that PYUB011 is the original code and has not been updated. It also told me that the PCM has to be updated a specific way for the connected car to know the update is out there. How? I have no idea but that's the beauty of AI, ain't it?

Every dealer's nightmare is a customer with and ODBII reader and the internet.

Thanks,
Tim

 

[MrViking]

Full disclosure here and apologies for wrong information. Unintentional I assure you. I learned a lot about the cooling system and especially, other things to be aware of.

My information regarding the PCM revs came from using Gemini. Note that I had many exchanges to get explanations and sources of the information so this wasn't based on a brief conversation. Gemini spoke of further revisions to the PCM code as if it were in existence. Somewhere. What happed is that it had concluded that since I had the K rev and there were still cooling issues, there was a later release that would fix what it thought was the problem. It took my symptoms, like temp swings when the outdoor temp was cold, and applied it's own fix to it, which was managing the shutters better in cold weather. It even put in quotes some of the exchange such as, "open based on engine load" and "closed until 205° F" when ambient temps are below 32° F. Having things in quotes would certainly lead one to believe that it was quoting a document it had found WRONG!!! The fix that Gemini thought it needed turned into a new, but non-existent revision of the PCM code, which it called rev L. It further created an existence of an M revision that changed the cylinder deactivation behavior since two cylinders not firing greatly changes cooling demands. Yet another piece of vapor-ware. You don't know how hard I had to push Gemini to finally admit that there really was no L or M code actually out there but there would be if Mazda actually fixes the new problem with the dummy plug which is wild temperature swings when the outdoor temp is cold.

So I really learned something about using AI and using the data in forums or with the dealer. This lesson can certainly be applied in many ways.

 

[cz5gt]

Whats your PCM code number?
starts with PY, PE, PA, PX..

 

[MrViking]

PX2G-188K2-K (in the original post)

 

[N7turbo]

Interesting fact: those shutters are not just related to cooling--they alter the drag coefficient of the vehicle at speed to improve fuel economy.