2012-2015 BMW 640i Ambient Air Temperature Sensor Guide
If your BMW's outside temperature reading is wrong and the A/C isn't working, this small sensor is the likely cause.
- A faulty sensor is the primary cause of incorrect outside temperature readings and A/C failure in automatic mode.
- The sensor is located in the front passenger-side bumper area and is an easy DIY replacement, taking less than 30 minutes.
- For this simple, non-critical part, an aftermarket URO brand sensor offers significant cost savings with low risk.
- No recalls have been issued by the NHTSA for this specific part on the 2012-2015 BMW 640i.
Symptoms of a Failing Sensor
A bad ambient air temperature sensor on a 2012-2015 BMW 640i has very specific symptoms. Because of its location, it is easily damaged by road debris, parking curbs, or even deep puddles. The most common sign of failure is an incorrect temperature reading on your dashboard. Often, it will get stuck at an extreme reading like -40°F or 122°F.
🎬 Watch: How to fix sensors stuck at these extreme readings.When this happens, your automatic climate control system gets confused. It may prevent the air conditioning compressor from turning on, because the car thinks it's freezing outside. This means your A/C might only blow warm or ambient air, even on a hot day. You may also get a Check Engine Light with diagnostic trouble codes (DTCs) like P0072 or P0073.
🎬 See how to test and fix the P0073 circuit code.Choosing the Right Aftermarket Part
When it comes to simple, non-critical electronic sensors, you don't always need to buy the original BMW part. For a part like the ambient air temperature sensor, a quality aftermarket brand provides a reliable and cost-effective solution. The installation is simple, so even if the part were to fail prematurely, the replacement process is not difficult.
URO Parts: A Good Value for This Job
Forum discussions among BMW owners show that while URO Parts is a budget-friendly brand, it is considered perfectly acceptable for non-critical components like this one. For a simple sensor that is easy to access and replace, saving money with a URO part is a practical choice. You would not want to use a budget brand for a complex or hard-to-reach part, but for the ambient air sensor, it is a low-risk repair.
Installation Location and DIY Repair
On the 2012-2015 BMW 640i (F12/F13 chassis), the ambient air temperature sensor is located in the front lower bumper area. You can typically access it by turning the front wheels to one side and removing a small access panel or a few screws in the fender liner, usually on the passenger side. The sensor itself is a small, probe-like component that simply unplugs from its wiring harness and unclips from its mounting point. No bumper removal is required, making this a very straightforward DIY job that takes less than 30 minutes.
| Part Type | Price Range |
|---|---|
| New OEM (BMW) | $55 - $75 |
| New Aftermarket (URO Parts) | $19 - $20 |
| Shop Labor | $75 - $125 |
Frequently Asked Questions
Where is the ambient air temperature sensor located on my 640i?
It is located in the front bumper area, typically on the passenger's side. It is often clipped into the brake cooling duct or the plastic fender liner and is accessible without removing the bumper.
Can a bad ambient temp sensor really stop my A/C from working?
Yes. If the sensor reports a freezing temperature to the climate control unit, the system will prevent the A/C compressor from engaging to protect it from damage. This is a very common symptom of a failed sensor.
Is this a repair I can do myself?
Yes, this is an excellent DIY task for owners of any skill level. It typically requires basic tools to remove a few screws in the wheel well, and the sensor itself just unplugs and unclips. The entire job can usually be done in under 30 minutes.
Are there any recalls for this part?
No, as of early 2026, there are no specific NHTSA recalls or Technical Service Bulletins (TSBs) for the ambient air temperature sensor on the 2012-2015 BMW 640i.
Helpful Videos
Technical Specifications
OEM Part Numbers: 65816936953 65816905133 65810141199
2-pin electrical connector, NTC resistor type.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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