E70 N62 4.8i Fault code E72B info needed
 

Need info on the A/C Fault code. Where i can find the description on these codes.

1) A/C K-Can 00E72B
2) Rain Sensor RLS 00A12E

Aux Fan running high when AC is ON.

how did you pull these codes?

I used OBDII and connect to the X5 and via Bluetoth connect to BMWhat app on Android phone.
That throws me these codes when ignition is ON or car is running.. These are suppose to be genuine BMW fault codes and not OBDII Pxxxx codes.

so no "P" codes?

No they are not "P" codes. I am not getting any P codes from OBDII app.
BMW codes are much accurate then OBDII codes. Initially I got 22 Fault Codes then I clear all of them but these 2 keep coming back and that's an issue.

Communication fault between the AC control and DME, this is what it is. Could be intermittent or you may have problem with the AC compressor activation. Th request to the compressor is sent by the AC control and executed by the DME.

The AC in the X5 is cooling great and observe no issue with the compressor. But their is an issue with Aux Fan running like a Jet Engine whenever AC crystal button is turned ON.
I think something is sending a wrong signal to Fan to run High when AC is ON. This could be the DME or whatever controls the communication. There is a history to it.

Last year my AC was not cooling, so I tried filling up the 134+ myself. Just after the fill up my Condenser leaks and all the freon leaks and Fan started running high. So took the car to an indy bmw and put in a new Condenser and pull all the freon and fill it up again. AC start working again but observe that Fan runs high when AC is ON. Told the Indy shop and he ran a code check last year and told me its due to faulty rain sensor. I couldn't believe what he said so just let it go. Now seeing the AC fault made me think something is wrong with AC module or some sensor which is causing this Fan running high and the fault code. Also called the BMW Dealer and left a message but he hasn't call back yet. Hope its something simple between DME and AC or some sensor. Already replace the coolant sensor few days back but that didn't help.

AC condenser fan is commonly enabled with high pressure at the compressor suction. On a simple system there is a pressure switch at the dryer.

The fan will not run at high speed because of a faulty rain/light sensor.
Now when I think of it, the actuation of the AC compressor could be done directly by the AC control and only the electric fan activation could be done thru the DME, and it makes sense in your case. If you dont have any other communication faults in the car next logical step will be to disconnect the RLS and see if the code will go away(and fan start to act normally). If nothing changes you can try to disconnect the AC control and check if the communication code for the RLD will go away. There is a big chance either AC control or RLS is shorting the K-line.

Last year I did remove the RLS sensor and fan still runs high but didnt verify the code since I dont have the code reader. Where is the location of AC control ? if I can access it easily I can try disconnecting it and see if Fan problem goes away.
I also read in another post the possible reasons for Fan to run high was High pressure which can cause the fan to run high. Not sure if removing freon and putting it back again will fix the high pressure issue.

Ac control is the unit with the buttons. You need to remove the trim and a few bolts to pull it out. High pressure could be suspect for the fan running at high speed, but you have this communication code. You have to read the actual values from the AC control.

more on possible causes for aux fan to run high all the time when AC is ON.

"...the electric cooling fan is controlled by the ECM via the output final stage. The output final stage is mounted on the fan housing, next to the fan motor. The fan is operated using a pulse width modulated signal. Fan circuit wiring is protected by a 50 amp fuse. Electric fan activation is based on the following inputs to the ECM:

• Radiator outlet temperature
  
• Calculated catalytic converter temperature
• Vehicle Speed
• Battery voltage
• Calculated A/C pressure
  

When the vehicle is first started, the ECM activates the fan briefly at 20% of its maximum speed, then switched off. This is for diagnostic monitoring. The voltage generated by the fan when it slows down (acting as a generator) must match the stored rpm values in the fan output stage to confirm that the fan is operating correctly.

There is a control module mounted to the aux fan housing that receives a variable signal from the DME, which then controls fan speed. It may be bad. The PWM speed control is inside the fan motor housing, it's speed is continuously variable from the duty cycle of pulses it receives from the DME.

So its either the PWM on the Fan housing is bad or DME is sending signal to PWM to run high seeing AC pressure is High.

AC has 2 pressure input Low and high, low is used to put the gas. I also see a sensor on the high side (small pipe).

Did a small test to verify the freon Gas. Put the gauge on low pressure side, outside temp was 70F, I got ~30psi within the Green range of 25psi to 45psi.
I dont have the Full AC gauge system to hook up the high pressure side to create a full loop, I have seen that selling in walmart.
Today I am observing that my fan is running but not that loud or high but that could change any minute as I have seen in the past.

You can just read the actual values in the AC control module and see what the pressures are and how many % fan speed is requested by the AC module.
Normally when the fan control unit goes bad the fan does not work at all. Most of the time, if the fan runs on highest speed all the time this is some kind of safe mode caused by a parameter going out of limits.

^^And how to read the actual values from the AC control. Do I need to hook up something or they are visible on AC control. I still couldn't figure out how to remove the trim on the AC panel in the Car where all the AC buttons are in the middle.

Thanks for your support @bawareca

Refrigerant Circuit Pressure Sensor

The refrigerant pressure input signal is a direct junction box input signal and is relayed to
the IHKA via the K-CAN. The IHKA requests actuation of the auxiliary blower by the DME
(ECM) depending on the refrigerant pressure.
The IHKA determines the relevant A/C compressor load torque on the basis of the input
signals from the pressure sensor and the compressor speed. The DME (ECM) control
units are notified of the load torques by the IHKA and used by the DME (ECM) as input
variables for actuating the electric fan

Is this could be the Culprit as shown in Red circle.

Again, you have to read the actual values to find the culprit.

I like to update and seems like My Aux Fan problem of running very loud when AC is turned ON is fixed.

After replacing the A/C pressure sensor on the High pressure line I don't hear the Aux Fan going crazy. The Compressor is still engaging and Car is Cooling fine but no more Fan sound.
I need to Vacuum the R134a at local shop before I remove the Sensor, I used 15/16" Wrench and it was quiet tight before it get loose. After putting back the new sensor I add ~12oz of R134a and bring to 28psi at 80F and it start cooling again. I believe E70 takes 1.1lb +- of R134a on a complete empty system.
Never over fill the R134a it can cause problems. I will check it out with local shop how much more I need.


See the 2 pics of the part I replaced $35 and the location of the part on my E70 N62.


Mfg Part # 64539181464
A/C pressure sensor located in A/C line from receiver-drier to evaporator.
This sensor attaches to the a/c line and detects the amount of line pressure for the a/c compressor to engage. Works in conjunction with the climate control system and the air conditioner.