Ford Scorpio Forum - Print Page


    
      
        Ford Scorpio Forum
        (https://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl)
      

        General >> Give/Need advice to/from others >> diesel overheat warning light
        
(Message started by: bernard_slade on Dec 4^th, 2012, 4:04pm)

Title: diesel overheat warning light
Post by bernard_slade on Dec 4^th, 2012, 4:04pm

my diesel overheat warning light is on even when the engine is stone cold so i suspect a dud sender or an earthed wire the sender must be on the engine does anyone know where it is located i have seen 2 possibles one with a green square plastic connecter and the other sitting at the rear of the head one must feed the temp guage which works fine then presumably one feeds the engine control module and maybe the overheat warning is a third sensor j think if overheat was fed to the computer it wouldnt enrich the mixture for it to start ::)

Title: Re: diesel overheat warning light
Post by Simmo on Dec 4^th, 2012, 4:23pm

Does This link (http://www.fordscorpio.co.uk/tdi-0996.htm) or the other one on the 'buttons' on the left help? :)

Title: Re: diesel overheat warning light
Post by Tompion on Dec 4^th, 2012, 5:30pm

ECT top of page 5 here:
http://www.fordscorpio.co.uk/manual/engines/tdi/TDIRem&Inst.pdf

It's one of those horrible drawings.

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 7^th, 2012, 2:10am

thank you both for your replies -i have identified the ect half way along the engine which relays temprature to the pcm but i still dont know what the wire going to what looks like a sensor at the rear of the engine does as it is not mentioned as needing disconnection on engine removal. when the weather improves i will try disconnecting the ect plug and see if the overheat warning light still comes on .the temp guage works perfectly and i dont know if that is also fed by the ect or another sender somewhere else although i havent seen any reference under cooling and normally such senders are in the head i will keep looking

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 7^th, 2012, 7:02pm

can anyone advise me how to upload photos to this site they are on my computer and also i have uploaded them to flickr but even failed to upload a pic to my profile but this site seems to have no upload provision ---help !!

Title: Re: diesel overheat warning light
Post by Tompion on Dec 7^th, 2012, 7:35pm

Have a look here:
http://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl?board=admin;action=display;num=1268569404

Title: Re: diesel overheat warning light
Post by Tompion on Dec 7^th, 2012, 7:41pm

Better drawing of ECT here:

http://www.fordscorpio.co.uk/manual/engineman/tdi/TDIECT.pdf

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 8^th, 2012, 2:56am

http://i1124.photobucket.com/albums/l578/slade405/ford%20scorpio%20diesel%20nov%201997/8254008816_f1e430b3f6_z.jpg
i can only hope this has worked the photo shows the 2 sensors i am talking about --with the engine cold disconnection of both did not extinguish the warning light

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 8^th, 2012, 3:40am

http://farm9.staticflickr.com/8064/8252959981_17f1acf3a6.jpg (http://www.flickr.com/photos/slade405/8252959981/)
8254008816_f1e430b3f6_z (http://www.flickr.com/photos/slade405/8252959981/) by bernie405 (http://www.flickr.com/people/slade405/), on Flickr

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 8^th, 2012, 1:36pm

today i see the photobucket photo that refused to take has miraculously appeared =anyway experimenting today shows the ect (green) must control input to the pcm but not the temperature gauge that is fed by the one further back i have labelled "what is this sensor" but neither seem to feed the overheat warning light that remains on with both plugs disconnected so it must be fed from somewhere else .the only other light that doesn't go out is the airbag light that flashes 4 then a pause i think this is a failure on seatbelt tensioner -im hoping to find a lead disconnected and remedy this maybe some previous owner has had the seat out and not put the wire back on but im beginning to think the overheat light will only be extinguished when the bulb burns out

Title: Re: diesel overheat warning light
Post by Snoopy on Dec 8^th, 2012, 3:38pm

I would have to presume that the warning light on may be caused by a faulty sender unit. Only trial and error with replacement will confirm, that is what i would do. Ask if anyone has a spare or old one you can use to replace it with.

I think the warning light on the TD model is controlled by the ECU and NOT the gauge sender.

Title: Re: diesel overheat warning light
Post by Tompion on Dec 8^th, 2012, 11:49pm

I knew I'd sent a link to someone on the mailing list with regard the sensors. Having got home and looked on that computer page 5 of this PDF confirms what the sensor are:
http://www.fordscorpio.co.uk/manual/engines/tdi/TDIDismantle.pdf

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 9^th, 2012, 1:19am

hi tompion thanks for that link it does confirm the sensors and is extremely useful i thought the same as snoopy that a faully ect sender unit might be the problem until i found that the light was still on with the ect disconnected -with the ignition having been turned off and then on again i now fear that the pct may have stuck in the light on position and doesnt reset when the ignition is turned off i suppose i can try removing the multiplug from the pcm and reconnect and hope that resets it -come to think of it disconnecting the battery might do the same job. if it is a dud pct only a facelift diesel pct will do and i suspect the number of those built was infinitesimally small so they will be hens teeth and most on offer will be pre facelift from arnitel disasters thanks again for both your inputs

Title: Re: diesel overheat warning light
Post by Tompion on Dec 9^th, 2012, 8:53am

The wiring diagram does show it as coming from the ECU but the ECU must receive the info from somewhere which I assume would be the ECT – only other I can think of would be the autobox temp sender but that seems unlikely as they're mainly manuals.
I think maybe Snoopy is eliminating the gauge sender as that only connects to the gauge.

If it is the ECT then disconnecting it may still cause the light to come on since with my 2.3 the fans will run if I disconnect the ECT. You could try a resistor across the terminals. Does the diesel have an inlet air temp sensor? You could try patching to that instead See here:
http://www.fordscorpio.co.uk/ectdata.htm

It doesn’t give a resistance for the ECT but click on the side link to the IAT and that has a table.

I don’t think sensors are all that dear, you only need to plug one in to test if that’s the problem no need to fit it.

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 9^th, 2012, 12:07pm

you are right i have ordered an ect sender and on your last point i wouldnt have thought of that its a really good point it does away with draining coolant etc

Title: Re: diesel overheat warning light
Post by Glyn on Dec 9^th, 2012, 10:49pm

I have never drained mine when changing a sensor- just let it go cold after running and when the sensor is removedthe resulting slight vacuum holds the coolant in except for a dribble -only needs a top-up if that !
Glyn

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 13^th, 2012, 4:59pm

today after changing the maf i fitted a new ect sensor hoping the overheat light would extinguish but no such luck so i now suspect a wiring short and located the c132 to check the 6 &7 terminals for cross connectivity with my multimeter -a probe in 6&7 producing a bleep would confirm that as the problem but i cant find out how the connector separates or where . i found one press point which lifted a catch somewhere but it all remains stubbornly solid as though it is still retained and if it is simply stuck i cant see how you can apply any leverage.anyone seen a picture of how to disconnect it i havent found anything on the site about it apart from the wiring diagram maybe im just thick and everyone else knows how to do it

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 18^th, 2012, 5:13pm

i did apply heat from a hairdryer to the c132 connector and opened it checke continuity and established no short exists between the c132 and the ecs sensor so no wires are touching that leaves c132 to pcm and of course the pcm itself but as everything else is working i will live with it for a while meantime the warning light remains stubbornly on even with frost on the bonnet

Title: Re: diesel overheat warning light
Post by adam on Dec 18^th, 2012, 6:18pm

Bernard

Are we sure the coolant temperature gauge sender shown as unknown in your pic has no impact on your overheat warning light?

Adam

Title: Re: diesel overheat warning light
Post by bernard_slade on Dec 31^st, 2012, 4:45pm

yes pretty sure with that disconnected the temp guage doesnt work but the overheat light stays on

Title: Re: diesel overheat warning light
Post by Matt on Dec 31^st, 2012, 6:25pm

Bernard,

what year is you diesel mate?

Ive got fords wiring diagrams and the technical service guide book in front of me atm, If you full fuse 16 from the main fuse box the light should go out?

from the manual its fuse 16 (7.5A)--violet/black cable or violet/blue cable depending on year--->pin 33 on instrument cluster -----> PCM ----> ground.

now depending on what year you car is will depend on what pin on the ecu the 12v feed is going to.

Again Depenging on year your ECT will either be on pins 53 and 58 (before 09/96) or 33 and 14 (as of 09/96)

Title: Re: diesel overheat warning light
Post by bernard_slade on Jan 1^st, 2013, 4:39pm

hi matt sorry didnt spot your post as it came up as a start to page 2 and i only just saw i have a page2 --yes pulling out fuse 16 extinguished all warning lights my diesel is build date nov 97 and is a facelift job i have checked the most likely wiring fault being the ect terminal to pins 6&7 at c132 and connecting the ect terms to 6& 7 shows continuity but cross connecting the multimeter pin 6to7 shows no continuity so no short in the most vulnerable wire so the problem isprobably between c132 and the ecu and as that area seldom gets disturbed its the area of wiring i would least suspect but it is looking that way i will need to check for no short in the wires between c132 and the ecu pins33 and14

Title: Re: diesel overheat warning light
Post by Matt on Jan 1^st, 2013, 6:26pm

Hi Bernard

you could just have a dry joint on the ECU plug, it would not be the first time ive know it and simply unplugging and replugging in can sort a few issue (even know it to sort dancing rev needles)

i'll get the diagrams out again in the week and go through the system

Matt

Title: Re: diesel overheat warning light
Post by bernard_slade on Jan 11^th, 2013, 5:39pm

taking a respite from trying to figure out dim dip wiring i suddenly had a thought about this overheat light which is permanently on ,in any other automatic model that light position is qverdrive on/ off . now my car being an auto diesel doesnt have an overdrive selector on the gear lever as it is the older A4LDe box not A4LDE . it just occurs to me that the light is telling me that overdrive is not selected. it could only be if someone in the past has changed the pcm for one used with the full electronic auto box. it would explain why i cant put it out but it is just a wild theorynow i will go away and think some more about dim dip

Title: Re: diesel overheat warning light
Post by Matt on Jan 13^th, 2013, 6:07pm

The PCM on the diesels is unique.

as you say its fitted with the older A4LDe which was also fitted to the 12v. The dash panel is also unique to the diesel so if its saying overheat then it is an over heat sensor error

Title: Re: diesel overheat warning light
Post by bernard_slade on Jan 13^th, 2013, 6:23pm

ok it was just an idea

Title: Re: diesel overheat warning light
Post by bernard_slade on Jan 29^th, 2013, 5:48pm

today i put scorp in a garage for problem starting which happily turned out to be a new set of gloplugs and the man said to me we tried to fix that warning light thats permanently on but we found the sensor on the bottom of the header tank but no plug and wires to plug onto it and without those wires connected it will always show overheating so now i know i need the plug and wires but where on earth do they go to? ive seen no reference to this set up in everything ive looked at or maybe i havent recognised it

Title: Re: diesel overheat warning light
Post by bernard_slade on Jan 30^th, 2013, 2:14am

the more i think about it i think my garageman was wrong about the overheat light because i would expect the headertank sensor to detect coolant level and illuminate the radiator auxiliary warning sign but strangely my rad icon illuminates and goes off behaving perfectly normally so that is getting a signal from somewhere else as the header tank sensor is not connected to anything .it is interesting just how little you got on later models for instance my old 1995 scorp ghia diesel saloon came withclimate control ,sun roof and cruise control but my facelift ghia x has no sun roof ,manual air con _with nowhere to put the pollen filter,and no cruise control as well as no door lights and no dim dip or bits i am still to realise are not there ::)

Title: Re: diesel overheat warning light
Post by bernard_slade on Sep 30^th, 2015, 1:46am

just to close this off it turned out my main wiring loom had become about 50 bright copper wires separated by dust
and two of the gloplug wires had fused together still miraculously running perfectly there was no allternative to scrapping the car as nobody could have remade the main harness to the main control modules another casualty of arnitel wiring