Temperature Gage

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johninderbyshire
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Temperature Gage

Post by johninderbyshire »

Xsara 2001 1.4 petrol.

Temp light comes on along with stop light, then fan kicks in and it all goes off, and then it goes round in a circle keeping doing the same.

Replaced a sensor that sticks out of the top of the head with a blue plastic bit on it (as advised by main stealer) and problem persists.

Q1, Does the fault store itself in the ecu? If so how do i get rid of it?
Q2, If not, any ideas about other sensors I should change as the water is not boiling or getting hot before the light comes on.

Sorry to be a pain, but its really annoying and my wife wont drive it untill the stop light goes away.

John
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AndersDK
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Post by AndersDK »

Q1-answer : NO !
Q2-answer : the radiator fan thermoswitch. At least check this circuit out thoroughly.

The reason is that the low-speed for the fans dont come on at first temp level. Then the temp raises further until the fans cuts in at high speed at level 2 temp. At the same time the engine just exactly hits the temperature ceiling and sets the red warning lamp temporarily.

Its imperative to get the fans cutting in at lower temp such you never see the red temp warning again. Else it may well cost you a cylinder head gasket replacement - a major and expensive repair task.

The controlling of the radiator fans is totally independent - out of the hands of the ECU. The ECU just stores a fault code if the engine misbehaves because of too high a temperature.
Anders (DK) - '90 BX16Image
johninderbyshire
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Post by johninderbyshire »

ok, so where is this switch located?

Already replaced head gasket, water pump, etc last weekend due to some other contributing factors. It has solved one prob we had, but not this one.
pugxpert
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Post by pugxpert »

would this car be too late for a bitron,symptoms sound like 2 pin brown coolant temp sensor open circuit with just stop light and over heat light on??
EP6T petrol turbo nice engine in the 207 GT and the new mini....
johninderbyshire
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Post by johninderbyshire »

ok, so now i am thick..... but what is a bitron??
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AndersDK
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Post by AndersDK »

Naah you're not ...

The bitron is the electronic lump controlling the fans - when you have air-condition fitted.

If you do NOT have aircon - then its the standard setup with the fan thermoswitch (item 7) like on this drawing :
http://www.citroen-pr.net/catalogues/il ... 410050.gif
Anders (DK) - '90 BX16Image
johninderbyshire
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Post by johninderbyshire »

i do have air con fitted...... so what next??
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Clogzz
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Post by Clogzz »

:mrgreen:

If you have air conditioning, there is Bitron.
I’ve had that fault on the Xantia, and cured it by giving the Bitron pins a good scrape.
A quick squirt of WD40 may fix it for a few days.
The brown temperature sensor and its wiring may also cause it, but there are no stories of the blue one causing it.
I’ve got posts on the subject here, but either the search has gone strange, or I have. :?
Here is something:

http://www.aussiefrogs.com/forum/showpo ... ostcount=9
2002 C5 2.0i AL4 230,000 km 76372389
johninderbyshire
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Post by johninderbyshire »

where is this bitron located then??
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Clogzz
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Post by Clogzz »

With a bit of luck, it's in the fuse box under the bonnet.
This photo goes for some petrol Xantiae. :mrgreen:
It's a box of clear metal, about the size of a cigarette pack, with 15 connecting pins.

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2002 C5 2.0i AL4 230,000 km 76372389
johninderbyshire
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Post by johninderbyshire »

bloke at garage wont put it onto a computer because he says it would be a waste of money.
He is certain on an electrical fault somewhere and said to go through all the relays and switches. He said it is safe to drive and ignore the warning as the car just isnt getting hot, its just saying it is!
john
JohnM52
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Post by JohnM52 »

pugxpert wrote:would this car be too late for a bitron,symptoms sound like 2 pin brown coolant temp sensor open circuit with just stop light and over heat light on??
Agree with this, same when these symptoms showed on Xantia. Check PRNet fro your engine type and car and look for Water outlet temperature switch sensor
Depending on model, there are three sensors, Blue, Green and Brown. Blue feeds temp guage, Green feeds ECU and brown feeds Bitron for cooling fan control.

Check to find out which is your and order the replacement sensor and problem should vanish.
JohnM
johninderbyshire
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Post by johninderbyshire »

problem solved!
Two resistors with coils have been replaced (they screw in next to the fan). One of the old ones had a completely broken coil, therefor andersdk was right in saying that the stage one fan wasn't cutting in, but the stage 2 was.

Thanks for all your help and suggestions guys.

John :)
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