The exact message is:

Electronic thermostat circuit fault. Last occurrence - Maximum signal

Does this mean it's grounded, or is recieveing a full 12V? I'm not 100% sure on how the electronic thermostat works. I appreciate there is a heater element around the Wax Stat' but not sure how that relates to this message?

Any thoughts welcomed

Dan 

Hi Dan,
I've had a bit to do with the Electronic thermostat and believe it is a coil in a wax element that if the ecar is running hot or under high loads ie you flooring it or towing up hill it will detect this and put the ground to earth via the ecu, which will assist the thermastat to open fully. There are 2 wires that go to this thermostat one is 12+ on ignition and the other one goes to the ecu which in turn puts it to ground when required.

Reason I know this is I carried out a mod (on Landyzone forum) which I wired the ecu (switched ground) wire perminently to ground. This had the result of having the thermostat fully open when the engine is warm, this has dropped the running temp of the engine from 106 degrees to a more reasonable 94- 96 degrees. Remember the electronic thermostat wouldn't open the thermostat on it's own it only assists it opening, the heat of the engine does the rest.

My car is LPG and so runs a bit hotter and wanted to keep the strain of the engine down since I have already had a head gasket. My belief is tthese engines need to run so hot for emmision purposes and since I am on LPG this really isn't an issue and no there is no change in MPG.

Anyway I'm not sure what your fault code means but I would suspect it has put it to ground, thus fully opening thermostat when engine is hot. Easiest way of checking is go into your hidden menu and look at you temperature of the engine. If it is running sub 100 degrees it is in fully open position if it is over 100 degrees it is shut and would presume a faulty thermostat.

Please look into this yourself as I am not an expert, this is just what I worked out by reading the Rage Manual on the electronic thermostat about 100 times until it made sense in my head.

Adam

dan this has come up on my scan with the rover com V8 facelift Range Rover Autobiography 22" wheels.
1976 Harley Davidson Iron Head Sportster

Ah, in which case I might not worry about it too much then... It might just be reading the code wrong, especially as it won't let me clear it. 

hi
i done the same mod as Adam to keep the temp lower because of LPG conversion(been done around 5 years now)
and the same fault comes up on the hawkeye
never had a problem with it so far

nige

Your all right in your replies if the OP had a 4.4 M62 BMW engine but he has the 4.2 S/C Jag engine

It doesn't have an electronically controlled engine thermostat, what it does have is two additional radiators for the engine oil and the gearbox oil which are electronically controlled so it is very important that you get this fault repaired very soon or serious damage will be done to your engine or gearbox.

EDIT........oooops sorry to cast dispersions on the rest of you I'm 4 years too late..... Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Last edited by Haylands on 23rd Dec 2015 1:05pm. Edited 1 time in total

And as an aside to those with the BMW M62...

The "O" ring that seals the electrical plug into the thermostat housing is known to degrade over time, this allows coolant to flow through the electrical plug and travel the short distance back inside the loom to the main ECU in the black box under the bonnet, it then rots out the connectors in the multi plug and destroys the ECU.

If yours is throwing the fault, then at the least, remove the plug from the thermostat and check for any signs of coolant, if you have the fault showing it does not mean that the thermostat is in the fully open position.....

The heating element within the thermostat is not designed to be used all the time, it is rated for very occasional use and as such if it is shorted out there is the chance it will fail and cause additional damage.

If you want the engine running cooler, (which is an excellent idea) then there is a conversion available to seriously reduce the temp and will make everything under the bonnet live longer..

http://www.ebay.co.uk/itm/80-C-Thermostat-...xyUrZSwcNg

And the widely spread "LPG runs hotter than petrol" myth is strictly true but in fact the burn temp is only 11 degrees Centigrade higher than petrol so pretty insignificant.

They run hotter on LPG because of poor fit or setup, they are running lean which is great for MPG but not good for engine temps.... Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Pete, the OP has a 4.2 now but when he originally posted i believe it was a 4.4 petrol... ... - .- -.




Y. O. L. O.
.

Oh yeah, people dragging up old threads again....

Oh well might help someone else who has a similar problem...........

 Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Pete

It does help a lot in fact, I think Dan posted this thread back up in answer to the question I asked in a thread
below this one Re- the fault code.

So my next dumb question, where is this thermostat hiding???

The problem is on a mates 4.4 BMW Vogue....



Old threads like old foggeys rock

Ziggy "Those who cannot remember the past are condemned to repeat it."
George Santayana
Puts away his cloth cap and donkey jacket
Goes and sits in the naughty corner

It's on the front of the engine below the throttle body, about in line with the top centre of the fan.... Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Thanks...........

Ziggy "Those who cannot remember the past are condemned to repeat it."
George Santayana
Puts away his cloth cap and donkey jacket
Goes and sits in the naughty corner