Ambient temperature sensor

[maltbie]

The outside temperature reading in my 23 GT2 is inacurate when the car gets wet. The reading can climb above 100F when it's 25F out. I suspect the temperature sensor under the bumper cover is getting wet somehow. Anyone ever dealt with this issue?

Car is under warranty, so I'll likely take it to the dealer when I have some other service issue to address.

 

[Thomby]

Looks easy enough to get to. You could try cleaning the contacts on the sensor & harness (brass brush & electrical contact cleaner or other light solvent), then put a bit of dielectric grease in the connector to prevent corrosion.

Or you could go a step further and test its resistance:

Kia Stinger - Ambient Temperature Sensor - Air Conditioning System

Kia Stinger - Ambient Temperature Sensor (ATS) - Engine Control System

 

[maltbie]

My KIA dealer replaced the ambient air temperature sensor today, or so they told me. The replacement sensor did not solve the problem.

 

[maltbie]

My KIA dealer replaced the ambient air temperature sensor today, or so they told me. The replacement sensor did not solve the problem.

I tried a third ambient air sensor. Same problem so the sensors must be fine.

I've discovered the outside temp is wrong only after the car has sat overnight. When I start the car in the morning, the displayed outside temp will rise about 40 degrees Fahrenheit over the actual temperature and stay elevated at this level until I turn off the car and restart it. Once I restart it, the displayed temp will quickly drop to about 2 to 4 degrees over the actual temp and stay this accurate until the following morning.

It appears the car's computer is causing the incorrect temp display. I've tried disconnecting the battery for 30 minutes, but that's only a temporary fix until the next morning.

 

[D.J.]

I've tried disconnecting the battery for 30 minutes, but that's only a temporary fix until the next morning.

So if you disconnect the battery, and reconnect the battery, the issue is resolved until the following day?

Where is the vehicle parked? What are the ambient conditions while parked?

You had mentioned that it was potentially related to getting wet, was that an erroneous assumption or is there still that assumption?

 

[maltbie]

So if you disconnect the battery, and reconnect the battery, the issue is resolved until the following day?

Where is the vehicle parked? What are the ambient conditions while parked?

You had mentioned that it was potentially related to getting wet, was that an erroneous assumption or is there still that assumption?

Yes, disconnecting the battery stops the pattern of the temp displaying 40 F too high. It reads accurately until the car has sat overnight and is started in the morning.

It's parked in my garage, which is usually around 55 F.

For the past year, it only malfunctioned when the car got wet. Wetness would cause the temp to display 110+ F even when the real temp was 25 F. When it dried out, the temp would display the correct temp. A few weeks before I took the car to the dealer, the check engine light came on, showing code P007100, ambient temp sonsor. The dealer installed a new sensor, cleared the code and drove it through their car wash. The car wash did not cause the temp to rise, so they thought they fixed the problem.

Wetness no longer makes the display show an elevated temp. The temp rises incorrectly only the first time the car is run after sitting overnight and is completely dry.

 

[D.J.]

Yes, disconnecting the battery stops the pattern of the temp displaying 40 F too high. It reads accurately until the car has sat overnight and is started in the morning.

It's parked in my garage, which is usually around 55 F.

For the past year, it only malfunctioned when the car got wet. Wetness would cause the temp to display 110+ F even when the real temp was 25 F. When it dried out, the temp would display the correct temp. A few weeks before I took the car to the dealer, the check engine light came on, showing code P007100, ambient temp sonsor. The dealer installed a new sensor, cleared the code and drove it through their car wash. The car wash did not cause the temp to rise, so they thought they fixed the problem.

Wetness no longer makes the display show an elevated temp. The temp rises incorrectly only the first time the car is run after sitting overnight and is completely dry.

Hmmm. I can't help. I can I my confirm that mine doesn't behave that way....

If it's not the sensor as it's been changed essentially twice, could it be high or intermittent resistance in that particular wiring harness? Difficult to confirm, and the dealer likely isn't going to spend time actually debugging the issue.

 

[maltbie]

Hmmm. I can't help. I can I my confirm that mine doesn't behave that way....

If it's not the sensor as it's been changed essentially twice, could it be high or intermittent resistance in that particular wiring harness? Difficult to confirm, and the dealer likely isn't going to spend time actually debugging the issue.

Excess resistance should cause the temp display to drop to below actual temp. If I disconnect the harness from the sensor, the displayed temp drops to -40, which is what it should do, as the circuit is open. If I join the two wires in the harness together with a paper clip, the displayed temp rises to 120 F, which is what it should do.

The problem is either there is too little resistance, causing the displayed temp to climb too high (which made sense when wetness was the cause) or the resistance is correct but the computer is showing an incorrect value. I think if the harness was bad, the pattern I'm seeing wouldn't be likely.

 

[Ozekia]

It could be damaged insulation on the sensor wires in the loom, these can short together with the water, when the loom gets showered with water or condensation in cold conditions.

 

[maltbie]

It could be damaged insulation on the sensor wires in the loom, these can short together with the water, when the loom gets showered with water or condensation in cold conditions.

I thought that, too, but I can flood the sensor with my garden hose and the displayed temp does not rise. If the insulation was damaged at the sensor connection, it should short immediately once it's flooded. I suspect the initial problem was caused by a loose connection at the sensor or a cracked sensor which allowed water to short the circuit.

Another possibility I have not explored is damaged insulation elsewhere on the harness that doesn't get wet when I spray the sensor with my hose.

I discovered a way to show the correct temp without disconnecting the battery. If I push the start button on and off multiple times (without my foot on the brake pedal) I can see the ambient air temperature rise on my OBD2 scanner up above 80F, even though it's actually only 55F in my garage. Interestingly, the displayed temp on the instrument cluster doesn't change while I do this. After cycling through about 10 on/offs with the start button, the OBD2 showed the temp dropping, but not all the way to 55F. In the morning, 8 hours later, the temp was displayed correctly on the cluster. During this whole time, the engine was not started and the car didn't move out of my garage.

Another possibility is that the computer is sending too much voltage through the harness, causing the displayed temp to be abnormaly high. Disconnecting the battery or turning the car's electronics on and off may be correcting the excess voltage problem. I could probably test this with a multimeter.