HVAC - excessive comm errors

W

Will

A2OC Donor
My interior fan is not working. The HVAC unit lights are all on as usual but adjusting the fan speed makes no difference.

My VCDS has an associated error. It simply says 'excessive comm errors'

In the past, unplugging the stereo has improved VCDS communications, but it makes no difference this time.

Can anyone please make suggestions for a diagnosis?

Thanks.
 
Hi, you need to change the latency on the port settings to something nearer 0. ie on a windows PC, right click my computer, device manager then right click the relevant coms port and go to advanced settings. You'll probably find the latency is set to something nearer 15 than 0 which is too high for decent communication. Cheers Rob.
 
I like the sound of that ie. free. Cheers.

I've bought myself a replacement s/h unit for £25. It's worth a punt I feel. If it doesn't resolve my issue I hope I can sell it for the same money.
 
My error codes are:

01271 - Positioning Motor for Temperature Flap (V68)

41-10 - Blocked or No Voltage - Intermittent

I'll have a search on the forum for suggestions, but I may be back for more help.
 
Resetting the codes and rescanning now gives:

01273 - Fresh Air Blower (V2)

17-00 - Control Difference
 
I think the first problem (temp flap) is nothing to worry about. I think it's the flap for the feet blowers and is common to stick intermittently on A2's. It's a big job to fix as it's buried behind the dash so probably not worth it.
I would google your other code number as this sounds like it's probably your problem. I doubt it's your Climate unit but you could try changing it if you have a spare. Have you checked the fuse?
Cheers Rob
 
Thanks, yes I've checked the fuse.

Checking through the forum this is not such an uncommon fault. In fact I had the same issue about 18 months ago. Back then I was able to apply 12v to the blower unit and it span OK. I reassembled and all was fine, until now.

I'll try a 12v feed again and see what happens.
 
This evening I partially removed the glove box and applied 12v direct to the fan motor. It rotated freely for about 10 seconds. So I then reconnected the 2pin connector and the air-con unit now fully opperates the fan speed. Result. :)
 
Will said:
This evening I partially removed the glove box and applied 12v direct to the fan motor. It rotated freely for about 10 seconds. So I then reconnected the 2pin connector and the air-con unit now fully opperates the fan speed. Result. :)
Click to expand...
Glad to hear you've solved the problem. Interesting to know should I or anyone else ever have a similar problem!

Cheers Rob.
 
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