2010 E350 Aircon Outside Temp -40?
04-10-2021, 05:07 PM
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W212 E350 Wagon
2010 E350 Aircon Outside Temp -40?
My Aircon has stopped working (compressor not going on). My scan tool is tells me outside temp on dash reading is 25C (dash shows this also) and second outside temp reading is -40. My scan tool further tells me the Aircon compressor is off due to outside temp being below -10C so this reading seems to be the problem. Can I reset the system so the -40 is corrected or force a change? Any ideas appreciated!
Background. I recently removed the bumper temp sensor to order a new one as it was reading about 7 degree C too high. I ran the car for a week with the sensor removed, this is when the trouble started. I have reinstalled the sensor now however the above issue is occurring and I have no AC. The car has the 3 zone comfort system.
Background. I recently removed the bumper temp sensor to order a new one as it was reading about 7 degree C too high. I ran the car for a week with the sensor removed, this is when the trouble started. I have reinstalled the sensor now however the above issue is occurring and I have no AC. The car has the 3 zone comfort system.
04-10-2021, 06:21 PM
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MY'14 W212 M276 3.5NA @55kMi
Does your scantool show you the A/C module, any DTC code?
Can you reset it from the scantool
-or try to pull the fuse related to backup power for that module?
- Else it could be a Xentry task🙂
Can you reset it from the scantool
-or try to pull the fuse related to backup power for that module?
- Else it could be a Xentry task🙂
04-10-2021, 06:34 PM
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-40 is classic Mercedes for faulty temp sensor.
It is possible your new temp sensor is defective? I would try reinstalling it and cleaning the connector.
It is possible your new temp sensor is defective? I would try reinstalling it and cleaning the connector.
04-10-2021, 08:11 PM
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Thanks for the suggestions. There were no DTC codes showing for the AC and no way to reset the system from the scan tool. I did try to reset it by removing the battery connector to the car for 30 seconds, however the issue remained.
However when I tried the AC system this morning (abut 14 hours after reinstalling the temp sensor) it was working fine again and the AC compressor was working. The scan tool was showing the correct temps and the compressor function was good. Also reading some others posts they suggest there maybe a 12 -15 hour reset period. I do not know why this would be the case and it seems strange however this seems to be correct.
However when I tried the AC system this morning (abut 14 hours after reinstalling the temp sensor) it was working fine again and the AC compressor was working. The scan tool was showing the correct temps and the compressor function was good. Also reading some others posts they suggest there maybe a 12 -15 hour reset period. I do not know why this would be the case and it seems strange however this seems to be correct.
04-10-2021, 08:24 PM
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MY'14 W212 M276 3.5NA @55kMi
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your experience makes this forum interesting to all others who share similar issues, great!
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