Ambient temp sensor fault

Wafu

Wafu

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T6 Pro
Addition to the second post.
Bumper off, took the new sensor off and check the resistance, checked the old sensor and the resistance is near to the new one, concluded that I have two serviceable sensors.
Checked for an earth from the plug wires, one has a good .002 resistance to earth, the other is show 01 on my multimeter. This would say I have good earth and a supply wire to the sensor.
Next step is to see what voltage I have to the plug from god know where in the van.

Does the sensor have a fuse? If so where is it please.
Does anyone have a wiring diagram for the sensor and any attached systems?
 
I have the same fault as you guys, the temp went from normal to random -figures, all the way up to -42 degrees, then it gives just dashes on the indication.
I’ve changed the temp sensor behind the grille, and plugged in my Carista. Job done I thought, but once I’d cleared the fault and the engine management light on the dash, the temp shows -16.5 with no engine management light.

I checked the code on the Carista and found ‘Outside temperature sensor: resistance too high - B103F1B code.

Anyone had this before? If so, can you point me in the right direction?

To help me understand the system, does the temp sensor wiring go through the multi plug on the offside, the one you disconnect when taking off the bumper?

Vehicle details are a 2018 Caravelle, Executive.
 
Wafu said:
Does anyone have a wiring diagram for the sensor and any attached systems?
Click to expand...
If you upgrade your membership to VIP, you can access wiring diagrams from the downloads section.
 
More to add.

I’ve now found that I have a permeant 6.8 volts at pin 2, with or without the ignition on. Pin 1 shows a solid ground to earth.
This test is done with the sensor removed and pins in the plug to the muiltimeter.

This does raise a question in my head, why is it supplied with 6.8 volts without the ignition? Can anyone help?
 
Wafu said:
This does raise a question in my head, why is it supplied with 6.8 volts without the ignition? Can anyone help?
Click to expand...

How long did you wait after turning ignition off? Van electrics turn partially on already before ignition eg by opening a door. Similarily, electrics stay on few minutes after ignition off - this is just a guess but I think the sensor might be powered in this partially awake state.
 
Ambient temperature sensor G17 connects to the instrument cluster directly (T32, blue connector pin 19) after the 14-pin plug near the horn.


1734462833941.png
 
Hi N10N, thanks for the info and the diagram. I might be looking at the wrong wiring diagram
The one I’m using is attached.
Further investigation would suggest you’re spot on. The voltage seems to stay supplied after the van is turned off. I have changed the plug on the ambient sensor and managed to get the temp to read -9 degrees stable.
It’s all pointing to a resistance issue in this signal line to and from G17.


The plug T32, are you saying it’s near the dual horn on my Caravelle?
This could be the source of the resistance.
N10N, thanks for taking the time to reply.

IMG_5490.png
 
Cheers mmi, this wouldn’t be the first time my van seems to have parts for a newer van. It seems to have all the build spec of a very late 2018 van, I’d even go so far as to say a bit of a T6.1 test bed.
Both you and n10n have given me something to look at tomorrow.
 
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Wafu said:
The plug T32, are you saying it’s near the dual horn on my Caravelle?
This could be the source of the resistance.
Click to expand...
No.

T32 is a connector attached to the instrument cluster.

T14 is the connector near horn, through which ambient temperature sensor wiring runs.
 
Well, this morning has been very fruitful and thanks to n10n and mmi, it’s seems to have shown me where and why my temp sensor was giving me jip.

T14 was flooded with water, funny that. A simple clean with electrical contact cleaner, gentle blow out with shop air and joint the two half’s of T14, bobs your uncle, the ambient temp works fine.

Many thanks to the guys and the wealth of information on the forum.

Merry Christmas and a happy VW New Year.
 
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