[e90yyc]

I've replaced my sensor with one from a scrapyard and am still getting this code... Yes, I've cleared it many times and it keeps popping up.

Has anyone else had theirs fail? I can't find many posts about it (probably because it's insignificant and nobody cares ha), so I'm trying to figure out what the likelihood is that it's the sensor versus wiring or something else.

Clearing codes and disconnecting AUC sensor will also throw a A6CF code, so it seems the fault is quite general and does not refer to the function of the AUC sensor itself.

If there is any way for me to test it with a multimeter too, I'd give that a try. I'll probably start by checking the actual harness for voltage, but I'm not sure what is normal here.

[jarad35]

Did you ever figure this out? I came across your post while searching for info on the AUC sensor, my AC isnt working and I have two codes I think are related.

The first is the same one you have re the AUC, the second is DRUCK_SENSOR (9C5E), which translates to pressure sensor. I am hoping this refers to the AC pressure sensor, which I have a feeling it does since I get infinite resistance across all the pins of the pressure sensor, but have 13.9V, 5V, and ground at the harness for the pressure sensor.

Do you know if the AUC sensor will prevent the AC compressor from engaging? I have the pressure sensor on the way, and just want my AC to work so if I need to get the AUC on the way I will.

[gbalthrop]

Originally Posted by jarad35

...Do you know if the AUC sensor will prevent the AC compressor from engaging? I have the pressure sensor on the way, and just want my AC to work so if I need to get the AUC on the way I will.

The AUC function is to detect pollutants in the ambient air when A/C is using outside air (as opposed to recirculating inside air). If it detects pollutants, it causes the recirculation flap to go to recirculate mode, but it does NOT shut down compressor function. A non-functioning Refrigerant Pressure Sensor WILL prevent compressor function however, so you will have everything you need to restore refrigeration circuit function when the new Pressure Sensor arrives (assuming you have a vacuum pump, refrigerant, etc. ;-).

Note the 2nd post in this thread:
https://www.e90post.com/forums/showthread.php?t=1085988

George

[e90yyc]

I did get this figured out. Had bad sensors. Got a good one and all is well now.

As George mentioned this won’t prevent anything other than AUC-specific functions from working.

[gbalthrop]

Originally Posted by e90yyc

I've replaced my sensor with one from a scrapyard and am still getting this code...disconnecting AUC sensor will also throw a A6CF code, so it seems the fault is quite general and does not refer to the function of the AUC sensor itself.

Originally Posted by jarad35

...I have two codes I think are related. The first is the same one you have re the AUC, the second is DRUCK_SENSOR (9C5E), which translates to pressure sensor.

Just to clarify: Since BOTH the AUC and Refrigerant Pressure Sensors (along with the Compressor Control Valve are connected to the JBE which is in turn connected to the IHKA, I would presume that either code (A6CF or 9C5E) was found by connecting to the JBE as opposed to the IHKA, or else found using Functional Jobs (assuming you are using INPA) and shown as being saved in JBE error memory?

Thanks,
George

[e90yyc]

A6CF was on JBE module, yes.

[jarad35]

Installed a new AC pressure sensor, haven't charged it yet, but still getting 0 bar reading in INPA. It doesn't fluctuate at all, which seems very strange to me. It's just a flat 0 bar, but I have signal and reference voltage to the harness, which makes me think the connection is fine.

Could this be the IHKA or JBE not properly interpreting the signal? I am thinking I need to test continuity from the sensor harness to the JBE, but I'm getting the correct voltages at the harness. Is there anything else I should be looking at here to try to fix this?

[jarad35]

For inpa reconnected, I still have a 9c5e error with the new pressure sensor. Found the pinouts for the JBE, I am not getting continuity between the pressure sensor earth, and pressure sensor signal or activation pins on the connection. I'm assuming this is a problem, since these must need to connect to ground.

Does anyone have any advice on where to go from here?

[jarad35]

Ok, so after some more digging around I noticed my voltage with the engine running is 14.9-15v (measured with a fluke from the + terminal under the hood to ground). I think this is too high, but I don't know if the ECU can request this much voltage. I'm afraid this is the core of the problem, and the over voltage is causing a problem with the AC sensor, or worse it's toasted my JBE.

How high can the alternator voltage safely go on an e93?. I can't get the ecu to load in inpa, I think I have the wrong ipo file. It tells me it's looking for zbel87_2, and I only have it without the _2.

[BillyOnions]

I have the same fault , is this a relatively easy job to do .?

[e90yyc]

Originally Posted by BillyOnions

I have the same fault , is this a relatively easy job to do .?

Super easy. Literally disconnect the harness and twist the old one out. Installation is the reverse of removal.

[Salzamani]

Originally Posted by e90yyc

Super easy. Literally disconnect the harness and twist the old one out. Installation is the reverse of removal.

I know the original one you bought that was from the scrap yard was bad. Was the one you bought last brand new? What was the cost? Is the function of the climate control noticeable after the fix? Air quality?

[e90yyc]

Originally Posted by Salzamani

I know the original one you bought that was from the scrap yard was bad. Was the one you bought last brand new? What was the cost? Is the function of the climate control noticeable after the fix? Air quality?

Ended up getting ahold of another used one that worked fine. At least no codes, which leads to me to believe the readings were within spec and therefore it’s functioning well enough.

Someone on this forum ended up sending me one, but frankly if I had to buy a used one I wouldn’t pay more than $20 Canadian, so like $15 USD max. And many here will say that’s way too much; my options are more limited up here though. New ones are about $75 USD, which I certainly had no intention of paying for something as nonessential as this.

To your question about air quality: Honestly, I’ve noticed no difference. I’m just the type of person who likes to fix shit when it breaks, even if the real-world impact is minimal. Since all it does is automatically recirculate air if pollutant levels exceed a certain threshold, I’m not surprised I haven’t noticed. Truthfully, there are instances when I would have expected it to activate recirculation but it hasn’t—times where I’ll smell strong diesel fumes, but nothing seems to happen.

I’m sure it works, I just don’t know at what thresholds it activates, and what pollutants the sensor responds to.

[Salzamani]

Originally Posted by e90yyc

Ended up getting ahold of another used one that worked fine. At least no codes, which leads to me to believe the readings were within spec and therefore it’s functioning well enough.

Someone on this forum ended up sending me one, but frankly if I had to buy a used one I wouldn’t pay more than $20 Canadian, so like $15 USD max. And many here will say that’s way too much; my options are more limited up here though. New ones are about $75 USD, which I certainly had no intention of paying for something as nonessential as this.

To your question about air quality: Honestly, I’ve noticed no difference. I’m just the type of person who likes to fix shit when it breaks, even if the real-world impact is minimal. Since all it does is automatically recirculate air if pollutant levels exceed a certain threshold, I’m not surprised I haven’t noticed. Truthfully, there are instances when I would have expected it to activate recirculation but it hasn’t—times where I’ll smell strong diesel fumes, but nothing seems to happen.

I’m sure it works, I just don’t know at what thresholds it activates, and what pollutants the sensor responds to.

Good details man. Thank you!!

I guess I’m wishful thinking here. I’m not sure I will ever buy a turbo car again. Heat is destructive to so many things. I can’t stand a anything that runs hot and turbos run hot. One problem that these BMW’s have is once the engine area gets fully warmed up from a drive the fresh air coming into the cabin is hot even though the outside air temperature is nice and cool. I never had this problem with any other car I’ve ever owned. Both of the BMW’s I’ve owned 535i & 335i both with the same turbo engines have this issue. I can override this heat in the cabin by turning on the AC which in my opinion only puts more of a load on the engine and makes it run even hotter. I don’t believe there is anything that is wrong with the engine it’s just a design flaw. I keep hoping to one day run into a fix but the truth is in all the forums I’ve ever looked with others reporting this issue no one ever reports a fix. Most people just say it’s normal and it’s just by design.

Yeah I’m the same way in that I want my stuff to work right but I’ve learned if your not careful you can waist a lot of money on these cars and when you go to sell it that money will not go back in your pocket. I do most of the repairs myself. I bought the car 2 years ago. It’s an 07 335i E90. It only had 64k miles. I paid $9400 for it. I’ve learned a lot about these engines since I owned 2 of them. I’ve performed about $8000(what dealer would charge)worth of repairs and preventative maintenance. If I was to sell it tomorrow I would be lucky if I get $7500 for it. Damn car always need something man! I’m thinking about running back to Toyotas.