AC compressor not pumping

Freddie Owner/Technician Louisiana Posted   Latest  
Case Study
2016 Fiat 500X Easy 2.4L (T ED6) 9-spd (948TE) — ZFBCFXBT8GP351464
Ac Compressor Not Working P0072
Bcm Code B107b11 External Temp Sensor
Ac Codes U202287 And U202187 External Temp Message

We can make the AC clutch come on with scan tool but it wont engage with the control head shows not requested.

p0072 comes on as soon as erased hard code, to make sure i am going the right direction when mirror is unplugged I get p0073

I am very limited on data and diagrams for the 2016 but the 2015 on Alldata shows the exterior temp sensor mounted in the RH door mirror so I removed the mirror and probed the wire to the ambient sensor and it shows 11 ohms at about 80 degrees and when I put a heat on it goes down to around 7 ohms.

I don't know the proper range on the sensor but the data on my scan tool is showing 190 degrees with mirror plugged in or not.

Michael Owner/Technician
Michael Default

I would find the pins on that connector and after unplugging it back probe a couple resistors till i get close to ambient temp and see what happens then. years ago before radio shack when away I bought a bunch of resistors and soldered them together sorry i don't remember the size but i use it to test fuel gauges and temp gauges my moving the test lead between the resistors i could get full…

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Allan Instructor
Allan Default

You wrote “I don't know the proper range on the sensor but the data on my scan tool is showing 190 degrees with mirror plugged in or not.“ If the temperature data on your scan tool doesn’t change with the mirror/temperature sensor plugged in or unplugged it sounds like you have a circuit problem in the wiring between the mirror/temperature sensor and the module it reports to. Test the circuits…

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Freddie Owner/Technician
Freddie Default

Thank you guys for the tips gonna give it a shot today.

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Eric Owner/Technician
Eric Default

Freddie, I would start by verifying the circuits between the exterior temperature sensor and the module it connects to. I'm not sure how Fiat works but other manufactures won't update the temperature until the vehicle is moving or until a set amount of time passes, they don't move like an actual thermometer does. This can make testing more difficult and confusing. The temperature should go to…

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Caleb Diagnostician
Caleb Default

Hey Freddie the good news is you already diagnosed the car! Ill explain why. #1 The Ambient Air Temp Sensor is hardwired to the BCM and functions just like any other thermistor on any other make. It has a 5 volt reference voltage on one circuit and an all time ground on the second circuit. As the sensor resistance changes with temperature it pulls the 5 volts higher or lower. #2 P0072 sets…

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