Hey guys, new here signed up just so I could post this. I’m having the common coolant control valve issues on my 2021 3. Problem is, I can’t get the cel to go off/code p0126 to trigger. I drive about 25 minutes to work each day back and forth, on the highway doing at least 60mph for at least 15 minutes. Temps near me recently dipped, around 35°F-40°F. This is the third commute in a row where the car has not reached operating temp and the gauge has stayed in the blue zone or right above it. Dealer doesn’t want to mess with it unless I have the code, though I experience every other symptom. How can I get the code to trigger? Is my commute not long enough? I have my heat set to 80°, will that play a factor in having the code trigger? Thank you.

 

How many miles on your Mazda?
What was the last service performed and what was it?


If you manually cause or trigger the code it will show as such if the Technician looks. That may not play out so well for you in the future.
The other thing is that you really have no idea what our temperature is to compare your dash indicators unless you actively scan the ECU and or install a manual indicator or the easiest quick way is with a hand held Digitaol diagnostic temperature meter.

If you physically went to Mazda should have at least entered your concern and look at it. If not insist! This way the concern will be entered into your VIN information.

Keep in mind that DTC and other codes are starting point to find a problem they are NOT always directly connect to the cause of the problem. So finding what you think is the DTC that caused a problem is a BAD way to start to find a the problem cause.

ASE

 

28,000 miles. Had an oil change in October and they told me that without a dtc they can’t do anything, I tried insisting. I just got the letter in the mail saying that they will cover a p0126 repair for 15 years or 150,000 miles by replacing the coolant control valve, but the code needs to be present even if you experience all the symptoms. It’s that common of an issue.

I have an obd2 scanner which does show the car hasn’t reached 160° in the last few drives. By “manually triggering the code” I just mean that I’m trying to meet the conditions that cause the code, but I’m not sure what those conditions are. I’ve been driving normally as I always do, but with the temperature in my area dropping the symptoms have been worse.

 

Your scanner reads the same as the dash indicator, you must confirm the sensor is not an issue.

Please try the other manual testing methods I mentioned and then report what you find.

 

will do, I can say after my 20-25 minute commute the upper and lower rad hoses are still pretty cold to the touch. During the summer when it was warm out everything was fine and normal. But I will try what you mentioned.

Do you know what conditions have to be present to cause p0126? I’m wondering if my commute isn’t long enough.

 

You cant go by the hose touch more or less but if what you say is correct then there may be a thermostat problem?. You see where this is going. If you don't *know how to correctly diagnose a problem and have the correct tools any vehcle from at leas production years 2000 (technically 1995) requires both .

I would however be insist that the dealership shows by way of a VIN report that they logged your complaint.

Your commute should be more then long enough and you can see this by looking at the ECU PIDs for the IAT's, CAT.f , monitored coolant F and ignition timing all at the OBDII diagnostic connector. The coolant Blue light goes off at coolant temperatures that exceed 129.9f

*ASE

 

yea there is a thermostat problem. 2019-2023 used a coolant control valve instead of a normal cork thermostat, which is why so many have this problem and why they switched back to the standard cork thermostat in recent years. Gen4 does not have a blue light for coolant. I’ll have to call the dealer and see what I can do.

 

Never herd the term "CORK THERMOSTST"? If by your mean conventional valve mechanical thermostat?

Also I can not find that there are "many" as you state having a problem. There is some TSB but none specific or needing more exact VIN and or other information to see if they fit the TSB and not all the cover Mazda as you state.
We use ALLData whci is updated every 6 months with any and all related platform concerns.

Many responses I give are generalities none specific for the exact years and model. So while some may not fit exactly your year they are still relevant Hense why I end some responses with ASE

 

yes I meant conventional thermostat. Ive replaced older gm cars thermostats that have used cork in the valve, my bad. Whereas this uses a coolant control valve, a whole different setup.

It’s a pretty wide spread issue amongst 2019+ Mazdas with a 2.5NA whereas the 2.5T uses a conventional thermostat so they are not affected. So much so that owners received a notice that the coolant control valve received an extended warranty, for that specific part failing. Just google “Mazda coolant control valve” and you’ll see what I mean.

MC-10201766-0001.pdf

 

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