Mystery sensor

[brodfather11]

Hi all,
New to this and Berlingos . a 2002 1.4 l petrol engine multiyspace.

On the engine block r/h side under the thermostat housing is a sensor of some kind, it has a one wire connector which was unplugged. It does not go into the coolant fluid space as nothing came out when I unscrewed to have a look at it. It sits in a empty dry pocket. Anyone know what it is for?. Haynes manual wiring diagrams do'nt show it at all, (I do'nt know why I buy them)

I need a handbook for it. Do'nt know what some of the switches etc. are for. any ideas where to get one?.

[tucker]

Can you put up a picture of it?

[colinh]

Got my manual from ComedyBay.

They usually knock down for about £15.

[brodfather11]

[attachment=442]

Can you put up a picture of it?

Hi Tucker,
Photos attached. one shows the position on engine (battery at bottom of photo.) There is 5volts at connector with ignition off or on. This thing seems to have an internal fault as a resistance test shows no conductivity between case and the terminal.

   
[attachment=442]

[Rustscrat]

Hi, I'm not up to date with the petrol engines but looking at the drawings - it matches up to item "4020" which is described as "engine coolant thermal switch" (1x green wire (405) with a blue connector).
In the drawing it is shown normally closed to earth and connected to the engine coolant temperature sensor (1220). If you say it has no resistance when tested try shorting the green wire to the engine block and see what happens, messeges etc. Keep away from the radiator fan just incase this starts up. Do you know what type of engine yours is ie, TU1, TU3 or TU5 injection?

Cheers alut:

[Image: 1247s00.png]

[brodfather11]

Hi Rustscrat,
I dont know what type of engine The engine no. is FSB740***** and vin VF7MFKFWB ********.
Earthing the feed for the mystery sensor has no effect that I can see. I tried heating it and checking resistance but no difference.
Yuo may have hit on the problem though, I've been having problems with the ECT ie getting code P0115 and P0118. and the coolant is showing at -40 d. f . This engine coolant thermal switch, if its not working would give a low coolant reading. If its meant to leak voltage to earth with temperature the ECT sensor will not work properly. What do you think?

[mikeB]

Hi Rustscrat,
I dont know what type of engine The engine no. is FSB740***** and vin VF7MFKFWB ********.
Earthing the feed for the mystery sensor has no effect that I can see. I tried heating it and checking resistance but no difference.
Yuo may have hit on the problem though, I've been having problems with the ECT ie getting code P0115 and P0118. and the coolant is showing at -40 d. f . This engine coolant thermal switch, if its not working would give a low coolant reading. If its meant to leak voltage to earth with temperature the ECT sensor will not work properly. What do you think?

It sure looks like a coolant temperature sensor. If you ground the feed wire the temperature gauge on the instrument panel should go high. If this sensor goes open circuit then I would guess you would get a very low temperature warning. As someone else said, make sure you are not near the fan as it may start up without warning.

[Rustscrat]

Hi, I would say that it should be normally closed when the engine is cold then opens when it gets to a certain temp.
Where are you reading the minus temp from and what code reader are you using?
Can you pm me your Rpo No. & full vin so I can identify the correct drawings as I'm not %100 that this is a switch.
Have a read of this.

http://www.permoveo.ltd.uk/tabid/122/OBD...fault.aspx

http://www.permoveo.ltd.uk/tabid/122/OBD...fault.aspx
:thumbsup:

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Also found you this.

[Image: 2eoxpux.png]
:thumbsup:

[brodfather11]

Hi Rustscrat,
I dont know what type of engine The engine no. is FSB740***** and vin VF7MFKFWB ********.
Earthing the feed for the mystery sensor has no effect that I can see. I tried heating it and checking resistance but no difference.
Yuo may have hit on the problem though, I've been having problems with the ECT ie getting code P0115 and P0118. and the coolant is showing at -40 d. f . This engine coolant thermal switch, if its not working would give a low coolant reading. If its meant to leak voltage to earth with temperature the ECT sensor will not work properly. What do you think?

It sure looks like a coolant temperature sensor. If you ground the feed wire the temperature gauge on the instrument panel should go high. If this sensor goes open circuit then I would guess you would get a very low temperature warning. As someone else said, make sure you are not near the fan as it may start up without warning.

Thanks Mike ,
The mystery thing is wired in with the ECT sensor and they are positioned quite near other on the engine c/head. When engine is running and I disconnect the ECT sensor the temp. gauge goes fully up and the fan starts running , quite safe as the fan is positioned in front of the radiator .

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Thanks Rustscrat
What do you mean Rpo. no.?
The diagram does show the (13) engine coolant thermal switch.
The code reader I used is a RAC. -HP104 (argos ) CAN OBD11 . I sometimes wonder about it as the users instructions are very poor. It has a freeze frame section which gives a reading of engine revs and coolant temp etc, The links will be very useful

I'll do another session under the bonnet now/today as the snow has now stopped and the thaw and puddles have disappeared, they are frozen, and if the sun melts the frost off the roofs and the birds start singing. I'll look at the nearby hills and if I can see them I know its going to rain /snow and if I cant see them it is raining. You gather I'm an outdoor man as I cannot get the Berlingo into my garage as its full of rubbish.

[Rustscrat]

Hi, the RPO number is usually on the drivers door pillar. See below.

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