Question about 2001 Audi A4

1 Answer

Are you me?

We have the same exact situation. I even changed the outside temp sensor twice, too, but like you, no luck.

The mechanic who normally is good at solving problems have not been able to figure out the cause either. It's getting warm in the area I live. I hope someone posts some ideas here, soon.

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  • 4 more comments 
  • pingu999_geo Jun 27, 2009

    I meant to comment on someone else's post. I would like to delete this post. How do I do that?

  • pingu999_geo Jun 27, 2009

    I meant to comment on someone else's post. I would like to delete this post. How do I do that?

  • pingu999_geo Jun 27, 2009

    Below is the original post that I meant to comment on. Exactly the same situation as me.
    mangoon on May 01, 2009

    have a 2001 Audi A4 Avant, Quattro, AT. The outside temperature reading
    on the instrument cluster will intermittently read as low as -45
    degrees. (The car
    is in Phoenix, AZ, so it;s nowhere near accurate). Trouble is, when
    this happens, the A/C "thinks" that it doesn't need to be on to cool
    the car, so all I get is searing Arizona heat blasting into the cabin.
    I've replaced the outside temperature sensor (twice! Both times with
    new Audi sensors) without any luck. I can find no other relay in the
    system. Temperature sensor --> temp display on instrument cluster
    --> A/C. When it does read incorrectly, almost every time I can get
    it to "reset" if I let the car sit for 5 minutes or so, then restart
    it. There is no consistency with outside air temp, driving time, starting it after leaving overnight, etc. Any thoughts on what could be wrong or how to fix it?

  • Richard Scordino May 11, 2010

    Don't think you can long as your'e here, what IS the problem? Perhaps I can help, maybe I can't....

  • Richard Scordino May 11, 2010

    Try posting the entire problem with details...when posting "I have the same problem" or what you wrote, your post does not come up near the original post...No one can figure out what you are talking about.

  • yadayada
    yadayada May 11, 2010




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  • 6,982 Answers

It sounds a lot like the control module isn't seeing the ambient temp signal. I don't think that the outside temperature sender would be the problem though...There should be a cabin temp sender that tells the a/c when to come on, otherwise if it relied on outside temp, it would never turn off. Till you find the real problem, you could temporarily add a toggle and fuse to the compressor itself, perhaps through the high and low pressure cut--off switches, to operate the a/c manually. Without actually being there to do hands-on testing, that's the best I can do for you. I really wish that they would standardize some of this stuff...I have lots of general mechanical experience as well as A/c, but not specific to Audi. Good luck with it and hope someone with experience on your system can help you out with that!

Posted on Jun 27, 2009


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Misreading outside temperature sensor on 2001 Audi A4

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The two sensors that will screw the system up the most are the intake and interior sensors. the system will function reasonably well with just those two sensors though it wont blend air temps between outlets if the sun sensor isnt working. If the outside sensor fails, it simply uses the intake sensor, if the intake sensor fails it will rely on the front sensor. However, since the intake takes priority over the outside sensor, if the intake sensor sends incorrect resistance info rather than failing, it will take priority and cause the unit to malfunction such as in your case.

The intake air sensor can be changed from the outside with patience. If it where me, I would pay the two hrs labor and let the dealer do it right.

Kevins Small Engine service,
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