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'99 E320 4Matic, '98 BMW M3/4, '94 E320
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13 Posts
Discussion Starter #1
About 3 weeks ago my A/C would start to blow cold then after 3-7 minutes later it would feel as if I hit the "EC" which feels like warm air blowing. The EC light does not come on or anything just that it feels like the AC compressor stopped. If I shut off the car, take the key out, wait a minute, and then restart the car the AC blows cold again. This may or may not solve the problem as 3-7 minutes can go by then AC may stop blowing cold again. There are times where I can drive 20 minutes+ and it blows cold steady.

What I have done: Replaced the outside temperature indicator temperature sensor this afternoon. Check the PSI of the system with it reading normal so no leaks or low refrigerant. Check senor data and error codes. I have erased the error codes and it does not come back.

Here is the sensor data:
Tonight
1-78
2-89
3-75
4-75
5-143
6-182
7-11 (started with 15 but i ran the car for 5 mins then drops to 11) this a shut off level?
8-109

3 weeks back
1-87
2-116
3-57
4-55
5-138
6-190
7-17
8-129


Error Codes:
B1227 - Outside temperature indicator temperature sensor (B14)
B1234 - Sun sensor (B32)

*Erased all codes and now nothing is back*

Thanks for your help!!
 

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1999 E55, 2001 E320, 1990 560 SEC, 2004 ML350, 2001 ML55, 1995 S500, 1998 SL500, 2010 E550 Sport zoo
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7,035 Posts
Those sensor "faults" are common and not the issue - yes, the system is taking the compressor offline for "protection" - you may have low/contaminated refridgerant - a evac/fill would show if this is the issue or not.

Possibly a fresh evaporator temp sensor - although the readings you post aren't as whacked out as some I have seen on the evap sensor as I have seen. Like $65 part aftermarket..
 

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'99 E320 4Matic, '98 BMW M3/4, '94 E320
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13 Posts
Discussion Starter #3
I used a 134a gauge to check the pressure and it was all within range. I guess if the computer is showing a different value then that might be at fault.
 

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'99 E320 4Matic, '98 BMW M3/4, '94 E320
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13 Posts
Discussion Starter #5
Update: As I drove the car today I had the actual sensor reading on #7 and I can see it drop from 16s down to 8-9s then the system automatically shuts down the compressor.

Is this the same sensor as the evaporator sensor?
 
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