# Outside Air Temperature (OAT) sensor problem



## UpstateNYBill (Jan 14, 2012)

Sometime over the winter, my OAT sensor began displaying incorrect outside temperatures. It would frequently display temperatures as low as minus 40 degrees fahrenheit, even though the temperature was much higher. Then it started to not display any temperature at all this spring unless it was raining, then it would diplay a constant minus 40.

Today I decided to take a look at the problem and found that the sensor had been flopping around behind the bumper and one of the wires was broken. I stopped at the local Chevy dealer and picked up a new OAT sensor since the old one was a little banged up. I repaired the broken wire, and installed the new sensor, and now the temperature display reads a constant minus 16 degrees.

I checked the connector and I have 5V DC, so there is power. I tried the old sensor, and that one also displays minus 16.

Any thoughts on what the problem might be?


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## BowtieGuy (Jan 4, 2013)

Is it possible to install the connections backwards? My next guess is the wiring wasn't fully repaired, or possibly broken further somewhere else?


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## ehousel (Nov 1, 2013)

the wire could have a higher resistance than normal, if it is a positive correlation oat I believe that could be an issue. Did you solder the wire? If not I would recommend that as a sensor such as this works with low voltage and amperage.


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## ChevyGuy (Dec 13, 2014)

Excessive resistance somewhere. The sensor's resistance increases with lowering temperature. So if the display is reading is too low, you've got excessive resistance in the connection somewhere.

One side is tied to power via a resistor (that's probably the +5V you saw). The other is connected to ground in the instrument cluster. So you might want to ohm that side.


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## UpstateNYBill (Jan 14, 2012)

Thanks, guys. Resistance in the ground wire does seem to be a likely cause, so I will investigate further.


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## peligro911 (Apr 8, 2015)

Also note the sensor does not fully start working after replacement until you drive the car a while .. Dealer recently replaced mine and told me to drive it more and if it didn't work to come back they would investigate more .. Sure enough to I hit the road at 50 to 60 it started adjusting 


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## Aussie (Sep 16, 2012)

I found mine slow to responde once Temperature reached around +40C, but now the weather is between 10C - 23C it works much faster. This week we are expecting about 8C at night so I will see how it goes at cooler temperatures. Onle four weeks out from winter here.


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## UpstateNYBill (Jan 14, 2012)

Started up the Cruze to take it for a drive to see if it would re-calibrate and the sensor is working perfectly. Didn't have to go anywhere! Sweet!


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## peligro911 (Apr 8, 2015)

UpstateNYBill said:


> Started up the Cruze to take it for a drive to see if it would re-calibrate and the sensor is working perfectly. Didn't have to go anywhere! Sweet!


Glad to hear !!


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## Goatmaster3000 (Jul 21, 2015)

I'm having this exact problem. Where is the sensor located and what do I look for?


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## Robby (Mar 1, 2013)

I will assume you have a North American Cruze.

The sensor is located in the small hole in the left (drivers side) fog lamp filler in the front bumper cover.
You must remove the lowest horizontal cover to see up at the back of the sensor……it just snaps into the housing.
There is a two wire connector that plugs into the sensor.

Any resistance, either a result of a disconnect, dirty terminal, or damaged wire, will result in a -40…..the lowest reading the system can show.

If all wiring/connectors check out then the odds are the sensor itself has failed…..I might add that a sensor failure, beyond physical damage, is the least likely item to fail.

Remember that the system is not instant and may take up to 15 minutes driving/running time to re-orient itself.

Rob


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## Goatmaster3000 (Jul 21, 2015)

Robby said:


> I will assume you have a North American Cruze.
> 
> The sensor is located in the small hole in the left (drivers side) fog lamp filler in the front bumper cover.
> You must remove the lowest horizontal cover to see up at the back of the sensor……it just snaps into the housing.
> ...



Thank you you for the info. My Cruze doesn't show a temp at all, but whenever it rains or I go through a car wash, I get the -40 and the ac quotes working. Once the car has sat for a day, the -40 goes away and the ac starts working again.


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## Robby (Mar 1, 2013)

Goatmaster3000 said:


> Thank you you for the info. My Cruze doesn't show a temp at all, but whenever it rains or I go through a car wash, I get the -40 and the ac quotes working. Once the car has sat for a day, the -40 goes away and the ac starts working again.


Thats rather bizarre…….I do not have the test procedure for the sensor itself but you may have found a bad one……the no readout unless wet is what has me thinking along those lines.

Has the car experienced any frontal damage in its past?

Rob


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## Goatmaster3000 (Jul 21, 2015)

Robby said:


> Thats rather bizarre…….I do not have the test procedure for the sensor itself but you may have found a bad one……the no readout unless wet is what has me thinking along those lines.
> 
> Has the car experienced any frontal damage in its past?
> 
> Rob


The carfax came back clean when I bought it, but that doesn't mean anything.


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## ChevyGuy (Dec 13, 2014)

I'd still start with checking the connectors and re-seating them. It could be one of those "oh, THAT's the problem" moment once you get in and look.


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## BlueTopaz (Aug 25, 2012)

Funny this thread should show up now. My sensor was reading 100 yesterday while driving around and crusing down the interstate and the outside temp was only 90. Not sure what is up. It stayed high all day. Have not driven it today. I guess if it keeps reading off it will be time to take it to the dealer.


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## Robby (Mar 1, 2013)

BlueTopaz said:


> Funny this thread should show up now. My sensor was reading 100 yesterday while driving around and crusing down the interstate and the outside temp was only 90. Not sure what is up. It stayed high all day. Have not driven it today. I guess if it keeps reading off it will be time to take it to the dealer.


On these hot days the sensor, because of its location, will read the heat coming off the pavement.

Odds are thats all you were seeing.

Rob


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## BlueTopaz (Aug 25, 2012)

Robby said:


> On these hot days the sensor, because of its location, will read the heat coming off the pavement.
> 
> Odds are thats all you were seeing.
> 
> Rob


I'm thinking the same thing since it was on new pavement. So it was really dark and probably was heat soaked.


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## Tomko (Jun 1, 2013)

I have a NIST certified weather station at home. Really nice unit with power ventilated shroud and everything. The readings from my Cruze are consistent with my home unit. However the radio or TV broadcast of the temperature is always several degrees different from my readings.


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