Toyota C-HR 1.8 Hybrid external temperature sensor is stuck at 50°C

[Huni]

Hello everyone,

I recently became the owner of my brother’s Toyota C-HR 1.8 Hybrid. Unfortunately, I don’t have a Toyota service center nearby, so I’m trying to find a solution here.

The external temperature sensor is stuck at 50°C. I visited an electronics specialist who checked the sensor, and it works fine—there are no broken wires—yet it still reads +50°C. Because of this, the automatic climate control system isn’t functioning properly and is completely confused.

If the sensor is fine and the wiring is intact, what could be the issue?

I would really appreciate any help. Thank you very much!IMG_7372.jpeg

[Huni]

WhatsApp Image 2025-01-29 at 08.13.55.jpeg
another picture

[jdmvip]

Congrats on the new car and that is a very weird issue. I would try and check for any codes and if the cost is not too much, consider swapping the sensor anyway.
Other than that I wonder if the ECU has an issue itself if it's not the sensor or wiring.

[Huni]

Congrats on the new car and that is a very weird issue. I would try and check for any codes and if the cost is not too much, consider swapping the sensor anyway.
Other than that I wonder if the ECU has an issue itself if it's not the sensor or wiring.

There isn’t a single error code. We ordered a new sensor, but it produced the same symptoms. If there are no error codes and the issue isn’t caused by the sensor or wiring, and the car runs fine with no other problems besides the malfunctioning climate control and incorrect temperature reading, how could the ECU be faulty?

[jdmvip]

Very interesting situation here. Well, the sensor we can assume is good since you have now tried two. This just leaves wiring and the ECU IMHO.

If the wires are shorted together at some point this is a likely explanation and then more remotely I think it could be the ECU.
How did you verify the wiring is good?

Also if you unplug the sensor do you get any reading at all?

Please make a pic thread for us!

[Huni]

Very interesting situation here. Well, the sensor we can assume is good since you have now tried two. This just leaves wiring and the ECU IMHO.

If the wires are shorted together at some point this is a likely explanation and then more remotely I think it could be the ECU.
How did you verify the wiring is good?

Also if you unplug the sensor do you get any reading at all?

Please make a pic thread for us!

Alright, I’ll have some time over the weekend to remove the sensor. I also have an OBD scanner, so I’ll check what the computer says. I’ll take some pictures as well.

Also, the auto electrician checked the wiring up to the computer. He mentioned some Ohm values and said that everything was fine up to that point.

[Huni]

IMG_7388.jpeg
I removed the sensor, and it still seems to show 50°C. Could it be a computer issue?

[jdmvip]

Is this a separate physical gauge on the dash or is it part of the computer/screen?
I would think either the gauge/display is wrong or there could be a short in the wire since it's odd even without the sensor that you get the same reading.

[Huni]

Is this a separate physical gauge on the dash or is it part of the computer/screen?
I would think either the gauge/display is wrong or there could be a short in the wire since it's odd even without the sensor that you get the same reading.

No, this is a separate program. I checked the live data in the computer using an OBD scanner. The program is called Carista.

What do you suggest? How and where should I proceed from here?

[jdmvip]

My best guess is to have someone else check the wiring for that sensor again. If there is a short perhaps this explains why it still reads 50C or it's a firmware issue or ECU issue.
If you can do any firmware update to the software, that may fix it, assuming it is really a firmware issue.