Do all Citroens lie?

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Peter.N.
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Post by Peter.N. »

My XM says, on what's left of the dot matrix display, "Slow down overheating" when I have just started it up from cold!
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Post by dnsey »

And then there's the oil level light, and the water-in-fuel light...
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Post by Clogzz »

Isn’t that the ‘brown sensor’ fault of the Xantia ?
Not sure about the XM, but the Zant has a brown temperature sensor on the thermostat housing to tell the Bitron what it thinks the coolant temperature is to operate the fans at either the low or high speed.
The plug and wiring are prone to intermittencies that cause the overheat indication fault.
When disconnecting the brown sensor, both fans should go to the high speed.
It’s possible that the fans are spinning when the fault indication is there.
That may not be audible because of the diesel sound, but may be worth checking for.
There are a good few topics dealing with the problem on the Xantia.
I’ll try digging up some, and list them.
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Peter.N.
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Post by Peter.N. »

You are quite right Clogzz, they are, I can hear them. If I turn the ignition off and on sometimes they will stop, but it doesn't happen often enough for me to be able to find it.
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Post by Clogzz »

Hi Peter,

There’s been a modification from Citroën for that fault:

http://xu10j4r.free.fr/xantia/notexantia.pdf

The main part of it was to hard-wire the intermediate plug from the brown sensor to the Bitron.
There was also the replacement of a single-pin sensor on the thermostat housing with a 2-pin one to change the switching of the temperature warning light.
Don’t see what use that is, because the switching of the cooling fans stays the same, and that’s the main problem, because if the fans go to the high speed and stay there for too long, they may overheat or wear the brushes, because the high speed I think is only meant for overheating emergencies of short duration.
Turning on the air conditioning sends the fans back to the low speed.
A clean and tighten of the connectors from the brown sensor to the Bitron may cure the fault.
On the diesels, the brown sensor is apparently easy to reach at the front of the thermostat housing.
On the petrols, it’s at the back, out of sight, and out of reach.
Never even been able to see or reach mine, which is a nuisance. :x
There aren’t many diesel passenger cars here because the tax regime doesn’t favour them. :evil:
Only Peugeot, Citroën and Mercedes sell diesel cars here.
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Peter.N.
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Post by Peter.N. »

Hi Clogzz

Thanks for that, I'm trying to learn French to! If it becomes a problem I will persue it, but as I say, it only happens occaisionally. Where do I find the Bitron on a 2.1 td?
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Post by Clogzz »

Hi again, Peter,

Sorry for the French, but I don’t know if there’s an English version of that modification.
Probably not, as it was a modification that got done for free in France, as a legal requirement at the time, even on cars that were years out of warranty.
Let me know if anything needs translating.
The Bitron is under the passenger’s side headlight, at least on the Xantia, not sure about the XM.
Difficult to see and reach, the battery may have to come out just to see it.
The fault will never be there for a duration that will enable you to locate it.
By the time you’re under the bonnet, it’s come good.
You may not need to reach for the Bitron connector plug.
The fault is much more likely to be at the sensor plug, or at the connector along the loom, where it comes out of the inner wing near the battery.
Pictures from the Xantia:

Image Image

Past midnight here, Image Image back tomorrow.
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Peter.N.
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x 1199

Post by Peter.N. »

OK thanks Clogzz. I have already checked all the sensor plugs and they all appear clean and shiny and moving them had no effect so I will have to find the Bitron. I take it that it looks like a relay, how many pins and what colour?
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Post by Clogzz »

Hi Peter,

The Bitron is a black plastic box of about the size of a packet of cigarettes.
They are not all the same, mine has 15 pins arranged in two rows.
The left photo above, click to enlarge, shows fewer pins.
The right photo shows the black Bitron box in its place on diesels.

The brown sensor is connected between pins 7 & 14 of the Bitron.
Cleaning them with WD40 is good for only a few days.
The pins are tinned with solder, and I’ve had to scrape mine with the rough end of a broken piece of metals hacksaw blade to get a permanent fix.
Here is the map, you’ll feel at home with it: :D

http://www.frenchcarforum.co.uk/forum/v ... hp?t=17012

Regards,
Terry.


Edit 2:36 PM:
This photograph shows the Bitron connector as it is on my Xantia petrol 1995.

Image

The pins are numbered 1 to 8 from top left to right.
The lower row is pins 9 to 15 from left to right.
Pins 2, 3 and 9 have no wire going to them.
The map confirms that.


Edit 3:03 PM:
Delayed reaction.
Does the 1996 UK XM have air conditioning ?
If not, it doesn’t have a Bitron for the cooling fans and overheat indication.
But then, it wouldn’t have that fault either.
All XM’s here have air conditioning because the buyers were expecting that of a car in that price range.
2002 C5 2.0i AL4 230,000 km 76372389
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