BimmerFest BMW Forum banner
1 - 13 of 13 Posts

· Registered
2003 530i 5-spd (swap)
Joined
·
418 Posts
Discussion Starter · #1 · (Edited)
What I've done so far is charge the battery fully and then cleared the error but it keeps coming back. I then measured the voltage at the connector and it's showing 4V. Shouldn't the voltage read 12V?

Does this point to a bad IHKA panel?

EDIT: I'm only interested in solving the AWP issue.

 

· Registered
2001 BMW E39 540i Automatic Sedan, 200 k miles
Joined
·
2,409 Posts
No, your IHKA panel is fine.
But you have a defective aux water pump , and a bad AUC sensor (known as aka "stink sensor").

The aux water pump can be repaired or even completely shunted. The AUC sensor can be replaced, or ignored -if you don't mind stinky air occasionally getting into the cabin. (The AUC is supposed to trigger fresh air circulation inside the car, it is smelly outside)
 

· Registered
2003 530i 5-spd (swap)
Joined
·
418 Posts
Discussion Starter · #4 ·
No, your IHKA panel is fine.
But you have a defective aux water pump , and a bad AUC sensor (known as aka "stink sensor").

The aux water pump can be repaired or even completely shunted. The AUC sensor can be replaced, or ignored -if you don't mind stinky air occasionally getting into the cabin. (The AUC is supposed to trigger fresh air circulation inside the car, it is smelly outside)
Then why am I only getting 4V at the connector? WDS shows IHKA providing power to AWP. :dunno:

 

· Registered
Joined
·
15,976 Posts
At what point in the circuit are you measuring 4 V? And is this with the pump connector disconnected, and are you measuring with respect to ground?
 

· Registered
2003 530i
Joined
·
2,292 Posts
There is a drawback to leaving the AUC sensor with the fault and you're in the habit of setting "automatic" mode with the recycle button. When that happened to mine I discovered it put the HVAC system into recycle mode permanently. This was particularly troublesome in the winter because it resulted in the windows (including windshield) fogging up with mist as the cabin became humid from my and passenger's breath. I suppose it would have made for stuffy air too. I'm pretty sure that taking recycle out of automatic solved the issue until I replaced the AUC, but it's 8 or 9 years ago & I'm not certain.

BTW, the AUC is not a "stink" sensor, although you'll find lots of references describing it as such. Rather it detects "oxidizeable gases", e.g. exhaust fumes and similar. So when properly working it will switch the HVAC to recycle if you're stuck parked behind a bus, but is no help if you run into a skunk.
 

· Registered
2003 530i 5-spd (swap)
Joined
·
418 Posts
Discussion Starter · #7 ·
At what point in the circuit are you measuring 4 V? And is this with the pump connector disconnected, and are you measuring with respect to ground?
Yes, measuring it at the pump connector (disconnected) between pins 1 and 2. Is this not the correct way of testing the circuit? What voltage should I be expecting?
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
Joined
·
24,597 Posts
Up there in that A11 partial module box are two components schematically indicated. What are they and what are their functions?

The boxed PNP transistor icon says that A11 is full of semiconductors - kinda like adjustable resistors, and that open rectangle is the schematic symbol for a resistor - a voltage dropping current limiting resistor. You should not expect 12 VDC across X122 - 1 and 2 unless the motor is being commanded 100% speed.
 

· Registered
2003 530i 5-spd (swap)
Joined
·
418 Posts
Discussion Starter · #9 ·
Up there in that A11 partial module box are two components schematically indicated. What are they and what are their functions?

The boxed PNP transistor icon says that A11 is full of semiconductors - kinda like adjustable resistors, and that open rectangle is the schematic symbol for a resistor - a voltage dropping current limiting resistor. You should not expect 12 VDC across X122 - 1 and 2 unless the motor is being commanded 100% speed.
As far as I know, WDS doesn't provide component level schematic.

OK, that makes sense that I wouldn't see 12V at the connector all the time when the ignition is ON. I did crank up the heat to max to force the AWP to turn on, and INPA showed it activating momentarily, but the error didn't go away.

I'll provide 12V to the AWP to verify that it does run. If it does, then the problem has to be either in the wiring or the IHKA?? I'm trying to resist throwing parts at it.
 

· Nuclear engineer
02/2012 X5 35d M57Y CPO 125+K miles NOKIAN WR G4
Joined
·
24,597 Posts
I have no idea what is ***8220;WDS,***8221; but I believe the component level schematic wiring diagrams are proprietary information, like copyrighted. Otherwise I could roll my own.
 
1 - 13 of 13 Posts
Top