# trouble code B0423



## MonkeyBusiness (Jun 11, 2009)

Just got a B0423 code: air mix door number 2 inoperative error. 

No idea what this could be, and it seems that I cant search this new forum setup, or I havent figured out how to yet. Any help or suggestions would be appreciated.


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## dkfackler (Feb 8, 2010)

Isn't that a climate code(heat or A/C)?


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## MonkeyBusiness (Jun 11, 2009)

I have no idea


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## MonkeyBusiness (Jun 11, 2009)

someone?


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## ps2375 (Aug 13, 2003)

there are no 'B' codes. How did you get this code from the car?


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## Anony00GT (Mar 6, 2002)

"B" codes are body codes. It's not a VAG code, but I guess it is theoretically possible that another type of scanner (from Snap-On or OTC maybe?) translated a VAG code into some kind of generic "B" code. 

What year and model? Automatic or manual climate control? Sounds like a problem with either a blend door or vent control door behind the dash.  If the heat and a/c work, and you can switch between defrost-panel-floor vents normally, I'd just clear it or ignore it.


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## MonkeyBusiness (Jun 11, 2009)

the car is 1999.5 jetta 2.0 5spd manual climate control. I got it scanned at my local auto parts store so its quite possible that the code got "translated". If for some reason the B really should be a P the code could have something to do with my cat or 02 sensors. I'm going to try and get someone with vag-com to scan it to see if there is a discrepancy. 

Also, my heat AC work fine.


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## ps2375 (Aug 13, 2003)

"P0423" would be "Heated Catalyst Below Efficiency". That would most likely be the cat is failing, if no other codes for O2 sensors are present.


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## Anony00GT (Mar 6, 2002)

Yes, but it makes sense that a "B" code would have the air door description attached to it. If he had said that the "B" code was for a cat efficiency, I'd agree that the B should be a P. 

Something definitely isn't adding up here. Get the car connected to a VAG-COM and see what comes up.


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## ps2375 (Aug 13, 2003)

Having NEVER worked with a generic reader, only the VAG-Com, I've never seen a "B" code, only the VAG codes and those have the "P" codes with them. And I've never seen anyone bring a code in that was not either from the ECU or TCM from one of those generic readers. Outside of those two modules, I don't know if they can read them. And a "B" code will not cause a CEL. And since he does not have Climatronic, the car will not generate that code. So, yes get it either on VAG-Com or the dealer tool(VAS1551) and see what the real deal is.


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## Anony00GT (Mar 6, 2002)

There are a couple scan tools beside VAG-COM that are very capable of reading most, if not all, modules in all cars, VW's included. However, they're very expensive (priced from $3500-$10,000), and generally sold only to professional repair shops as shop equipment. In fact, Snap-On took VAG software and simply modified it to work with the unique button configuration on their MODIS scanner. LAUNCH took VAG software and configured it to work with their touch-screen scanner design. Still though, I can't figure how he got a "B" code from a VW (a scanner discrepancy is the only possibility I can think of) or how he's getting an air door code from a manual climate system... 

Also, it's good to know that Ross-Tech's VAG-COM is also an excellent generic OBDII scan tool for any make/model from 1996-present. If you want to play around with generic OBDII functions to learn how they work, plug the VAG-COM into any car's OBDII port and click the "OBDII" button on the first screen.


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## ps2375 (Aug 13, 2003)

Anony00GT said:


> Also, it's good to know that Ross-Tech's VAG-COM is also an excellent generic OBDII scan tool for any make/model from 1996-present. If you want to play around with generic OBDII functions to learn how they work, plug the VAG-COM into any car's OBDII port and click the "OBDII" button on the first screen.


 Yup, I have had to do that a time or two. But the ones at autozone have little capability other than to scan the engine module, AFIAK.


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