Climate Control Fault Code

P

p1lyp

Member
My aircon doesn't blow cold air. I've run a VCDS scan and it comes up with:

18043 - Powertrain Data Bus: Missing Message from A/C Controller
P1635 - 35-10 - - - Intermittent

Any ideas gratefully received.
 
P1635 is the A/C manifold fault I think. Replacement part is £20. Replacing the part on a RHD is about 2 days effort (full dash out & refit). LHD is about 4 hours, there's a video on youtube on how to do so.
 
Do you have climatronic/auto climate or manual climate? Any unsual stuff happening on the controller if you have climatronic? Fault sounds like the message from the controller isnt getting to the ecu and then activating the flaps to mix the hot cold air etc. So that could be the climatronic unit itself. Could try a spare old unit for £30-40 off ebay if climatronic
 
p1lyp said:
18043 - Powertrain Data Bus: Missing Message from A/C Controller
P1635 - 35-10 - - - Intermittent
Click to expand...
On which module was this fault code found?
It won’t have anything to do with why the air conditioning isn’t blowing cold.

Cheers,

Tom
 
The module was Address 01: Engine.

Is there anything I can check before going for a recharge?

Thanks for the input.
 
Thanks for the info.

All this fault code means is that the data connection between the engine management unit and the climate control unit was briefly lost. This may have happened if the climate panel was briefly disconnected whilst changing the stereo, fitting the komfortblinker, fixing the ashtray mechanism, swapping climate control buttons, etc. It’s logged as an intermittent fault, which further backs up this theory. It could be historic, from many years ago.
A diagnostic scan of the climate control unit, not the engine management unit, may provide much more appropriate clues about the cause of the non-operational air conditioning.

Cheers,

Tom
 
Thanks Tom, I had the climate control fascia out to change the buttons which may explain the code. I guess I'll need full VCDS rather than the lite version to scan the CCU.
 
p1lyp said:
Thanks Tom, I had the climate control fascia out to change the buttons which may explain the code. I guess I'll need full VCDS rather than the lite version to scan the CCU.
Click to expand...
There us no scan limitation on Unregistered Lite. You can scan every controller. But you can't do controller settings, you need to register Lite ($99), for that.
I'd check connections to the HVAC controller, and check it's physical condition.
And, as always, make sure you're battery is fully charged, and earths are good.
Mac.
 
Ross Tech tells users to ignore any intermittent fault code with A/C. Have you checked refrigerant pressure? Have you checked that the compressor is not seized?

RAB
 
p1lyp said:
Thanks Tom, I had the climate control fascia out to change the buttons which may explain the code. I guess I'll need full VCDS rather than the lite version to scan the CCU.
Click to expand...
There us no scan limitation on Unregistered Lite. You can scan every controller. But you can't do controller settings, you need to register Lite ($99) for that.
I'd check connections to the HVAC controller, and check it's physical condition.
And, as always, make sure you're battery is fully charged, and earths are good.
Mac.
Edit: Good advice from @RAB too.
 
I ran a scan on the HVAC module and it came up with a couple of intermittent faults which I gather can be ignored:

4 Faults Found:
01272 - Positioning Motor for Central Flap (V70)
41-10 - Blocked or No Voltage - Intermittent
00818 - Shareware Version. To Decode all DTCs
30-00 - Please Register/Activate
01273 - Shareware Version. To Decode all DTCs
17-10 - Please Register/Activate - Intermittent
00796 - Fan for Interior Temp Sensor (V42)
41-10 - Blocked or No Voltage - Intermittent

The compressor doesn't seem to be seized. The central part doesn't rotate at all by hand at rest.

I've done the toggle from LO to HI and back many times without effect.

Battery and earth are fine.

How does one check refrigerant pressure? Is this in VCDS?

Thanks again one all for your patience and contributions.
 
p1lyp said:
I ran a scan on the HVAC module and it came up with a couple of intermittent faults which I gather can be ignored:

4 Faults Found:
01272 - Positioning Motor for Central Flap (V70)
41-10 - Blocked or No Voltage - Intermittent
00818 - Shareware Version. To Decode all DTCs
30-00 - Please Register/Activate
01273 - Shareware Version. To Decode all DTCs
17-10 - Please Register/Activate - Intermittent
00796 - Fan for Interior Temp Sensor (V42)
41-10 - Blocked or No Voltage - Intermittent

The compressor doesn't seem to be seized. The central part doesn't rotate at all by hand at rest.

I've done the toggle from LO to HI and back many times without effect.

Battery and earth are fine.

How does one check refrigerant pressure? Is this in VCDS?

Thanks again one all for your patience and contributions.
Click to expand...
If this is the first scan, clear all faults in the HVAC Controller, go for a drive, then scan again. This is because, until fault are cleared, they remain, codes do not auto reset, so some of codes you see on the first scan may have been triggered long ago, and therefore not related to the current problem.
I would also, as a priority, fix the issue with the internal temp sensor fan. I suspect if the HVAC Controller can't read the internal temp, the AC can't run.
Mac.
 
As Mac has said..fix the issue with the internal temp sensor fan. You will most probably find that the fan has sucked loads of debris into it and could now be unable to rotate. Remove the climate panel from the dash and you will see the fan secured to the rear of the intake grilles. remove the screws to give both the fan and the grilles and duct a good clean out. Reassemble and before you push the climate back into the dash start the car and the climate. Look to see if the fan rotates smoothly and freely.
 
Cleared the codes, went to Lidl and rescanned and look who's come out to play: 🤣

1 Fault Found:
00818 - Sensor for Evaporator Outlet Temperature (G263)
30-00 - Open or Short to Plus
Readiness: N/A

I'll get hold of a sensor and let the missus know her delicate hands are going to be put to good use!
 
If your vehicle is RHD, it's not an easy job. Not that it's that easy with LHD. Might be dash out.

RAB
 
I might have to second that, its tucked right up there. Be very cautious with the plastic as it will be brittle in and around the HVAC under there. Totally doable but long winded. Better than lying under the car and getting covered in crud though! Best of luck sir.
 
Changing the G263 sensor is a pig. All repairs are, of course, worthwhile, but this will not cure the lack of air conditioning.

Cheers,

Tom
 
timmus said:
Changing the G263 sensor is a pig. All repairs are, of course, worthwhile, but this will not cure the lack of air conditioning.
Click to expand...
Surely it will if that is the only fault (and everything else is in order).

RAB
 
A failed G263 sensor will limit the air conditioning to something like 75%, but the air conditioning continues to work just fine without a signal from the G263. It’s only really in seriously hot environments, like Sicily, that you’re likely to notice a failed G263’s impact upon the air con.
There are plenty of ways in which the air conditioning system can fail that don’t log a fault code at all. In these instances, using VCDS to log live data/status is the key to pinpointing the issue.

Cheers,

Tom
 
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