dieter_schmid5
Vehicle HVAC Problem Resolved with Sensor Check
Summary of the thread
A 2020 Mercedes CLA hybrid experienced HVAC issues, blowing hot air with a warning light on the speedometer. Initially diagnosed as a refrigerant compressor failure, the repair shop suspected a defective air conditioning control unit. However, a suggestion to check the pressure sensors revealed a faulty sensor, which was causing the system shutdown. Replacing the sensor resolved the issue, saving significant repair costs.
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4 comment(s)
dieter_schmid5 (community.author)
Pressure sensors, huh That's interesting I'm not sure if they checked those specifically They mentioned something about checking the refrigerant levels, but nothing about the sensors themselves Is it possible for a faulty sensor to completely shut down the air conditioning system like that And if so, wouldn't that throw a different error code than a compressor failure
patriciafox1
Yes, it is entirely possible for a faulty pressure sensor to disable the entire system The car's computer relies on these sensors to ensure safe operation If a sensor reports an abnormal pressure reading too high or too low, the system might shut down to prevent damage As for error codes, sometimes a faulty sensor can indeed trigger a generic compressor failure code, as the system interprets the lack of pressure as a compressor issue Considering the cost of replacing the compressor, it may be worthwhile to specifically request that the workshop thoroughly test all related sensors and wiring before proceeding This could potentially save you a significant amount of money and avoid unnecessary repairs
dieter_schmid5 (community.author)
Thanks a million for suggesting the pressure sensor check I took your advice and asked the repair shop to double-check everything Turns out, you were right It WAS a faulty pressure sensor causing all the chaos They replaced it, cleared the codes, and now my car air conditioning is blowing ice-cold air again The final bill was a fraction of the original quote You saved me a ton of money and stress Seriously, you're a lifesaver
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MERCEDES
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CLA
patriciafox1
I understand your frustration It sounds like you are dealing with a complex issue I encountered a similar problem with my 2016 Audi A4, although the exact root cause was different My vehicle HVAC system presented almost identical symptoms: failure to cool, error codes, and warning lights In my case, the issue was traced back to a faulty pressure sensor in the refrigerant line, which then triggered a cascade of problems Did the repair shop specifically test the pressure sensors or conduct a thorough diagnostic of the entire automotive cooling system before concluding that the compressor is failing It might be worthwhile to explore alternative causes before committing to such a significant expense