Climatronic T4 Multivan: Troubleshooting Guide

Hi,

I'm dealing with a really difficult case right now.
T4 Multivan, year 1999, with this dual-zone climate control system.
The ventilation in the front of the car isn't working at all, while in the back, it only works on the two highest settings.

During the initial error code check, the following error occurred:
01273 - Fresh air blower V2.

Subsequently, the blower control unit (J126) was located on the fan, the Climatronic control panel was above it, and relay 114 (J323) was located underneath the control panel.

The error remains the same.
After performing an actuator test with VAG-COM and clearing the error codes again, these two errors appeared.

Address 08: Heating/Climate Control.
Control unit part number: 7D0 907 040.
Component and/or version: CLIMATRONIC 0002
Encoding: 00000
Workshop Number: WSC 00000
2 errors found:

01086 - Speedometer sensor (G22).
64-10 - Currently not verifiable - Sporadic.
00792 - Pressure switch for air conditioner (F129)
35-00 - -

I'm really starting to feel desperate.
And what the hell does a speed sensor fault in the Climatronic system have to do with anything?

Hi!
The speed signal might be needed when the Climatronic system adjusts the air distribution flap to achieve a consistent airflow within the vehicle, even at higher speeds.
Regarding the other issues... does the fan motor itself still work? Have you checked that directly?
However, I don't have Climatronic myself, so the experts here can probably provide more information.

Best regards,
Dirk.

The ventilation system is working perfectly again.

It was only due to relay 140.
"A VW mechanic told me that it might be related to the climate control system."

Unfortunately, the problem with the speed sensor is still there.

Two speculations:
A) The speed signal can only be evaluated while the vehicle is in motion (similar to how the camshaft sensor was always reported as a fault when reading the data on G3 gasoline engines with the engine off).
B) The climate control system receives the speed information via the K-bus, which is currently not possible because the diagnostic system is connected to it.

Both are explicitly just speculations. However, I would check the first one by reading the error codes while driving.

Regards,
Sure, here's the translation:

"Guste" is a German word that means "gust" or "gust of wind." It can also be used to describe a sudden burst of something, such as laughter or anger.