Engine coolant/High Temp warning message


2020 AWD GT, 2008 FWD GT
I was driving uphill on the Grapevine (I-5) about 60 mph and needed to pass a slow car in my new CX-9 GT. I didn't floor it, but the engine was definitely revving. Suddenly I received a "High Engine Temperature/Engine Output may be limited" warning message. Indeed the engine temp had spiked near the red line. The outside temp was 94 degrees. I feel like the car started to limit output, but I also I let off the throttle and slowed to 60 mph. Immediately the engine temperature started dropping.

Has anyone else experienced this warning message? This is the first time experiencing this type of warning in any vehicle. I'm certain I've accelerated while going uphill likely in 100 degree weather using other cars but never noticed the engine temp spiking. Certainly my older cars would not have been smart enough to provide a warning or cut the power.
At those speed there are usually enough airflow to cool engines in general. I have not seen this issue arise with mine. The temperature stays pretty steady all the time. I would keep an eye on that temperature gauge in the future to see if it fluctuates a lot in driving and when stopped at red lights and i would mention it to the dealer as well at my next visit.
Last edited:
Mazda CX-9 Grand Touring 2016
@GT4GT, your owner's manual shows how to check the level of the cool coolant. Your new car shouldn't be low, but check everything. The dealer's predelivery inspection ain't the greatest.

How could GT4 look at the air shutters at the grille to see if they're opening correctly?

Do take the car to the dealer. It could be a failed fan relay, or the shutters, or sendor, or something else. Of course the temperature indicator isn't an actual gauge, it's an electronic display of what a sensor is reading.
2016 cx9
Please check that there is a black box behind the headlight with a fan relay inside. If loose, the fan will not work.