Outside temp sensor 6-7 degrees too warm?

[not_too_shabby]

It's about 35F here this morning with frost all over the ground and roofs, ice on people's cars and the mazda is saying it's 41F? Is the temp sensor located too close to the engine or is mine defective? It's nice to know when you are in the mid-30's so you can be careful of ice on the road. I noticed that the temp displayed on the vehicle after getting in it after having it sit outside in the cold temps this morning was up to 50 and as soon as I started driving it dropped into the 40's again so it must be picking up some heat from the engine.

 

[Mazda3]

The sensor generally doesn't read acurately until you start driving to get some airflow through it. Mine will normally read about 2C too warm, which would be about 3F-4F. It will sometimes read warmer when I first start it, until I start driving. This has been the same with the 4 or 5 other cars I've had that had Temp display.

 

[not_too_shabby]

The sensor generally doesn't read acurately until you start driving to get some airflow through it. Mine will normally read about 2C too warm, which would be about 3F-4F. It will sometimes read warmer when I first start it, until I start driving. This has been the same with the 4 or 5 other cars I've had that had Temp display.

Even 3-4F is a big difference when you get close to freezing. I'm pretty disappointed as temps here often hover in the 35F range in the morning. My VW temp sensor was more accurate. If I drove my VW and parked it outside in 40 degree weather, I would came back to it an hour later it wouldn't be showing 53F like the mazda is doing. It would be very close to the outside temperature. Anybody know where they have this sensor at?

 

[Mazda3]

I believe the sensor is in the lower grille area. I don't know if the 3F-4F is a correct conversion or not. I just know that mine is consistently about 2C too warm which I find acceptable. 6-7 degrees consistently after driving a few blocks to get airflow through the sensor is probably not normal. The dealer will probably tell you a couple degrees variance is normal and I think it is, but if it's out 7 degrees all the time than something needs to be adjusted or replaced.

 

[squidly]

I also have a Mazda 6 and that temp sensor is much more precise than my CX-9. You'd think they'd use the same part. Maybe it's all in where the sensor is placed.

 

[Mazda3]

I also have a Mazda 6 and that temp sensor is much more precise than my CX-9. You'd think they'd use the same part. Maybe it's all in where the sensor is placed.

Maybe it is something specifically with the placement in the CX-9. I'm driving a CX-7, so I can't speak for the CX-9 specifically, I just assumed they would be the same. We also have a Tribute and previously owned a 06 Mazda 3 and 04 Mazda 6 which the temp reading was the same as the CX-7.

 

[not_too_shabby]

I'm going to compare it to the other car in our garage and see what it says after sitting in the garage all night. They should both just pick up the ambient air temperature with no influense from a warm engine.

 

[not_too_shabby]

Just an update. I checked the temp in my garage this morning with both cars cold. It was two degrees higher than the benz next to it which is acceptable. My guess is the temp sensor is being influenced by the the heat generated from the engine and is causing the sensor to not read the actual outside temperature accurately. I'll have to look around and see if it can be mounted in a spot that causes it to pick up the temp of the air from the outside.

 

[cccx9]

Both my CX-9 and my Nissan Altima read a few degrees F too warm until I get moving above 40 mph. I think some cars just have better placement for the sensor.

 

[not_too_shabby]

This morning in my garage the MB and the cx-9 both read 60F. So at least at warmer temperatures it accurate till the engine starts apparently. It doesn't seem to matter how fast I drive, it's not picking up the outside temp sufficiently, likely due to the placement of the sensor. When it's 28F outside, it's saying it's 35F. It probably doesn't take much heat from the engine to throw it off 7-8 degrees.

 

[CX9 SportOwner]

ours is dead on as long as we aren't idling

 

[Mazoom]

This is interesting. I brought our 08 CX9 in for some warranty work, and I brought this up. Of course, they brushed it off, saying that it was within 1-2 deg of other cars in the lot. Of course when I was picked up, the reading in an MB was 5 degrees cooler than the Mazda... And seemingly the correct reading.

Out of the 5 cars in the household, the Mazda's is definitely the worst off. Heck, even my 14 yo Jeep reads much more accurately! WTH?

 

[SeCX-9]

This is interesting. I brought our 08 CX9 in for some warranty work, and I brought this up. Of course, they brushed it off, saying that it was within 1-2 deg of other cars in the lot. Of course when I was picked up, the reading in an MB was 5 degrees cooler than the Mazda... And seemingly the correct reading.

Out of the 5 cars in the household, the Mazda's is definitely the worst off. Heck, even my 14 yo Jeep reads much more accurately! WTH?

There has to be some type of defect with the design or placement. I don't have this problem at all, but it's definately something people have reported.

 

[todd92]

Ours is always 5 degrees to warm.

 

[not_too_shabby]

It's really p*ssing me off as we routinely drive over passes where it is very important to know if it's 40 degrees or 34 degrees and adjust your awareness for black ice accordingly. I found the sensor. You can see it through the grill in the front bumper. It's held in place by this metal bracket that seems to shield it from the incoming air flow. I think the bracket is also reflecting heat onto the sensor from the engine. I'm tempted to drill a couple holes in it. I noticed that when the car was parked over night in the garage with our other car, both cars would be within about a degree of each other. The garage is usually 55 degrees this time of year. So either it is less accurate when the engine is running and putting off heat or it is less accurate at temperatures close to freezing.

Another annoyance is the length of time it takes for the temperature to get close to ambient. By the time we drive our mercedes out of our neighborhood, approximatley 30 seconds it's tempeture reading has dropped 20 degrees. I need to drive the mazda 5 minutes before it gets close to the outside tempeture.