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BMW 3-Series (E90 E92) Forum > BMW E90/E92/E93 3-series General Forums > General E90 Sedan / E91 Wagon / E92 Coupe / E93 Cabrio > AC goes on and off



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      07-17-2019, 04:35 PM   #1
HDFEBREZE
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AC goes on and off

So my AC has been driving me nuts. last year it would work for like 15-20 mins then go off for 5 and then go back on , this year it goes on for like 30 seconds and then goes back off. Ive had it refilled, i replaced the pressure senor visible on the passenger side next to the valve cover. As of today i am getting no cold air. Ill be lucky if i hear it kick on for a second. The code im getting is this.

Air conditioning / Klimaanlage
Fault Code: 009C5D
Fault Explanation: :Current sense f. driver supply / Knieausstroemer
servomotor right motor address 26hex / Monitor pressure sensor
supply / Probes Right heat exchanger / Belueftungstemperaturfuehler
right

I feel that i have the least knowledge on the AC system when it comes to my car so any advice on where to start looking would be greatly appreciated.
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      07-18-2019, 08:52 PM   #2
HDFEBREZE
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bump
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      07-19-2019, 12:40 AM   #3
gbalthrop
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This is for a 2010 535xi I presume per your "Drives"?
Not familiar with that model, so please furnish last 7 characters of your VIN for lookup of correct info on TIS:
https://www.newtis.info/tisv2/a/en/

What Scan Tool/Software are you using to read that code and get any Definition or Details?
What is the SGBD or Short Code of your IHKA Module? There are different definitions of that code depending upon Module SGBD. If you were using INPA, the Module SGBD would appear at top of screen or Menu when you connected, or you could find it in "Identification" of IHKA Module.

SWAG from partial info thus far is that the Power Supply from the IHKA Module to the Refrigerant Pressure Sensor is intermittent due to bad wiring or connector, but need requested info to get correct TIS circuit diagram. Here is Definition of 9C5D per BMW Fault Code Lookup:
9C5D | IHKA: Refrigerant-pressure-sensor supply | ihka60

If the Sensor's Power supply is intermittent, the pressure signal is also intermittent and when pressure signal falls below 3 or 4 bar, the Compressor Valve deactivates & NO refrigerant is pumped.

George
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      07-19-2019, 01:07 PM   #4
HDFEBREZE
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Quote:
Originally Posted by gbalthrop View Post
This is for a 2010 535xi I presume per your "Drives"?
Not familiar with that model, so please furnish last 7 characters of your VIN for lookup of correct info on TIS:
https://www.newtis.info/tisv2/a/en/

What Scan Tool/Software are you using to read that code and get any Definition or Details?
What is the SGBD or Short Code of your IHKA Module? There are different definitions of that code depending upon Module SGBD. If you were using INPA, the Module SGBD would appear at top of screen or Menu when you connected, or you could find it in "Identification" of IHKA Module.

SWAG from partial info thus far is that the Power Supply from the IHKA Module to the Refrigerant Pressure Sensor is intermittent due to bad wiring or connector, but need requested info to get correct TIS circuit diagram. Here is Definition of 9C5D per BMW Fault Code Lookup:
9C5D | IHKA: Refrigerant-pressure-sensor supply | ihka60

If the Sensor's Power supply is intermittent, the pressure signal is also intermittent and when pressure signal falls below 3 or 4 bar, the Compressor Valve deactivates & NO refrigerant is pumped.

George
Hi George, I appreciate your response. The VIN is: WBANV9C55AC390884

I was using the Carly for BMW App.

Everything I got related to the AC read was directly copy and pasted above.

I will do a scan with INPA and screenshot what I get.

Thanks again.
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      07-19-2019, 01:27 PM   #5
hassmaschine
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Have you had your windshield replaced?

there's a humidity sensor built into the window that controls the fan speed on auto. If it's broken, the fan will go crazy (up, down, up, down, up, down) on auto mode.
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      07-19-2019, 06:17 PM   #6
HDFEBREZE
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Quote:
Originally Posted by hassmaschine View Post
Have you had your windshield replaced?

there's a humidity sensor built into the window that controls the fan speed on auto. If it's broken, the fan will go crazy (up, down, up, down, up, down) on auto mode.
No, I haven't, but I did replace the humidity sensor last year. The fan inside the car works fine. It's the ac itself that isn't pumping cold air.
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      07-19-2019, 09:53 PM   #7
kens
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I have a 3 series and you have a 5 so I don't know if this will pertain to you. But I had similar if not the same symptoms.

I tracked it down to a corroded harness connector, behind the glove box. It was also melted. I wiggled it around until everything worked again and taped it up, trying my best to brush off as much of the corrosion as I could in the process. Once the recall went out - I got it replaced asap due to fire hazard safety concerns.

Maybe this helps, maybe not

Last edited by kens; 07-20-2019 at 02:31 AM..
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      07-19-2019, 11:06 PM   #8
gbalthrop
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Quote:
Originally Posted by HDFEBREZE View Post
...The VIN is: ...C390884
I was using the Carly for BMW App. Everything I got related to the AC read was directly copy and pasted above. I will do a scan with INPA and screenshot what I get...
Using your VIN last 7 (C390884) here is the circuit for the Refrigerant Pressure Sensor (B97):
https://www.newtis.info/tisv2/a/en/e...ontrol/kQ0qLyH

That Sensor, B97 is MIS-LABELED on the schematic -- it is NOT a "Coolant Pressure Sensor" but rather REFRIGERANT (R-134a) Pressure Sensor. I would use a Multimeter to determine which of the three Pins of Connector X10591 is the Voltage Supply to the Pressure Sensor, as the Code you posted (9C5D) appears to indicate that voltage supply is intermittent, possibly due to bad wiring or connector issue.

As I interpret the Schematic linked above, the Pressure Sensor, B97, is powered via the Green/Black wire at Pin #3 of Connector X10591, and here is the TIS "Connector View":
https://www.newtis.info/tisv2/a/en/e...00910/CTKjhhLZ

The control voltage is probably 5V, rather than a full 12V+, as measured in reference to ANY Chassis Ground. Here is the "Installation Location", according to TIS, of the Refrigerant Pressure Sensor, and it is MORE exposed to the elements and road spray/ debris than the similar sensor on my 328xi which is toward the rear of the engine compartment:
https://www.newtis.info/tisv2/a/en/e...200910/S9FoSro

If you are handy with INPA, you should be able to connect to the IHKA (A/C) Module, and read F4 Fault Memory (Fehlerspeicher) and Copy the ScreenPrint to Paint in JPG format, and attach that JPG file here to educate all of us. I trust a proper translation of the INPA Fault Memory screen will be more helpful than the Carly graffiti. Google Translate does a good job translating technical German, at least if you KNOW what the proper English terminology is, and can select the best synonym from multiple choices provided by GT:
https://translate.google.com/#view=h...te&sl=de&tl=en

While connected to IHKA Module, check the F5 Status Menu for "Analogports" (F5 > F1 Analogports is path/name on E9x INPA Menu system). That screen on my E91 shows Refrigerant Pressure (Druck Kältemittel) in "bar" units in "bar graph" format with pressure value, as well as Evaporator Temp (Temperatur Verdampfer). Of course if the Pressure Sensor is showing Pressure in the range of 13 bar (190 PSI) and Evaporator Temp of <10C, then the refrigeration system is working and you should have cool air.

If the Pressure Sensor value suddenly decreases below ~ 4 bar and the Evaporator Temp rises, you almost certainly have a wiring/connector fault in B97 and its connector. You might also try manipulating, moving or shaking the Sensor wiring to see if that causes change in Parameter Values of Pressure & Temp.

Please let us know what you find,
George
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