Skip the auto shop - Our mechanics make house calls

Q: outside temperature thermometer way off, a/c not working, check engine light is on

asked by on

hi there, my girlfriend has a 2015 bmw 328. she was out of town on a long weekend, and when she got back and picked up her car, which was parked in her sister's neighborhood, there were a few things acting strange:

  1. her thermometer is telling her the outside temperature is -40 F when it was actually 80 F
  2. her air conditioning isn't working
  3. her check engine light is on.

she thinks someone may have messed with her car while she was gone (she read something online that this can occur when wires are snipped)...any idea what may be causing these issues?

Thanks so much! Pat

My car has 15000 miles.
My car has an automatic transmission.

A: Hello. The reading of minus 40 degrees does...

Hello. The reading of minus 40 degrees does indicate that there is an open circuit in the sensor circuit. This will cause the A/C not to work and the Check Engine Light to come on. The sensor is in the front under the front bumper bottom cover. Look for damage underneath from hitting curb stops and you may be able to find the problem. If no damage is found, then have the sensor checked to see if rodents have chewed the wires or the sensor is damaged. If you need help having the problem scoped out, a certified technician from YourMechanic, can come to your car's location to inspect the entire A/C system in order to have this addressed.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Quits running multiple times

Hey there, thanks for writing in about your 2010 Lexus HS250h. Your problem is most likely the power integration relay/module (what you're referring to as the horn relay). The component is used to supply power to the horns, keyless entry...

Q: Recently my 2011 Kia optima ex GDI turbo has begun to decelerate when going uphill. The check engine light has been lit up for a month.

Hi there. Sounds like the turbo is not functioning correctly. The turbo may have a broken shaft or the intake fans are broke. When the turbo is not working, then the engine will not accelerate properly, especially under a load....

Q: Engine oil leaking

Hi There, To the extent you are receiving a message indicating oil is needed ASAP, I would recommend scheduling an oil change and inspection as soon as possible. When your engine is substantially low to this point, serious engine damage...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...