My vehicle is a 2015 Volkswagen Passat Wolfsburg edition. I ran over a squirrel the other day on the driver side of my car and it has done some damage to my bumper shield and also a sensor. This is the picture of the wiring harness that the sensor connects to (sorry it was not as clear as I hoped it would be)enter image description here

It has PA06 and 9805940 written on it, looking that up did not help me much. The check engine light is now also on and throws this code: U0423 and also looking that up did not help. One last thing is the TPS light keeps flashing for a minute and then stops and stays on

The sensor seemed to be connected to something that is by the driver side wheel but I have no idea where it was connected to. Any help would be appreciated

Edit: Just wanted to add that this vehicle is a california emission (not that this matter) And also the fan seems to be always on even from a cold start, wonder if the ECU is doing that as a protection measure. Also that plug has only 2 pins on it so that sensor shouldn't be that complicated I will take better pictures and post them but would appreciate any help

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    The PA66 is just a material code for a certain polyamide, often used in automotive. You'll find it (or similar) on almost any plastics part of your card. The long number is the part number.
    – sweber
    Aug 11, 2019 at 7:14
  • Which is the drivers side of your car? Do you sit on the left or right of the passenger?
    – HandyHowie
    Aug 11, 2019 at 8:18
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    Is the thing you have in your hand still connected to the car? If so, can you take a photo of where it is located?
    – HandyHowie
    Aug 11, 2019 at 10:14
  • obdii.pro/en/code/U0423
    – Moab
    Aug 11, 2019 at 18:15
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    "Going to the front" suggests it may connect to a temperature sensor, either at the radiator (so it reads some aspect of engine coolant temperature) or mounted in the bodywork (perhaps behind the grill, or to the side) to read ambient air temperature. Aug 11, 2019 at 23:36

2 Answers 2


U0423 Refers to the instrument cluster or the module that send data to it not receiving valid data from one of its sensors. Translation: A squirrel dislodged it and its not happy. Check the front passenger side wheel to find the location of the sensor and how it is mounted.

  • I checked the passenger side and can't find anything similar to it
    – method
    Aug 11, 2019 at 23:30

I have asked @David to post this as an answer but I think he forgot. He was correct, the sensor in question is the Ambient Air Temperature Sensor. Installing a new one fixed the problem, thank you all!

  • Thanks, @method. I didn't see your prompt, happy the information was correct. Aug 21, 2019 at 15:03
  • And for future reference if you return here: the reason I didn't see your prompt was that your reference to me in the comments ("@David") was truncated, so notice wasn't sent to me, but instead went to a user (or users) named "@David." A reference to my complete username ("@DavidSupportsMonica") would have raised a flag for me. Sep 3, 2020 at 16:48

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