Probably way off base. but "running on" was a sign of timing being over advanced. Could it possibly be an intermittent error with the crank position sensor causing a timing shift?
I'm not quite sure how the crank position sensor works on the FF.

Also caused by engine needing a decoke which I would think wouldn't apply to yours and wouldn't be internittent.

Bit of a very,very, long shot but you did ask for any suggestions.  John
2008 Stornoway Grey 3.6 Tdv8 Vogue - SOLD
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Think you will have been here with dynamic pipe replacement but just incase, have you checked the engine earth? Once you have the drivers wheel arch liner off you can see/clean the positive lines that connect at the back of the arch. The earth is less easy as it sits behind the alloy inner wing. This had partially disintegrated but engine would start easily and never had an issue so had discounted it initially. There is also the earth on the transfer box which although looked mint was remade. I am guessing starting was using this route.

Does your IIDtool's configuration show 2 types of faults set to show? I can't remember which one it is that isn't on ex factory but needs to be set on to show all faults. L405 D350 SE Carpathian Grey D5 19" rims

Thanks for taking the time to post chaps....

John, I had that thought but it's diesel so won't run on because of timing, the fuel pump is still on so it's not getting the message to shut off... When it's "running on" it's ticking over just as it does normally...

Qwerty, Yep, I have looked at all the earths and ground points I can find, they are on the list to check again... I'll look for more than last time...

Graeme, Pretty sure mine is set to show all faults, I will check though....

At least it only happens now and again and fixes itself when it cools a bit..  Pete
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It is called "pending faults" and by default are not shown.

Last edited by jimmie on 5th May 2025 6:00pm. Edited 1 time in total

Graeme and Jimmy,

I thought I had selected it, had it years now...

Anyway...

Click image to enlarge

Click image to enlarge

You might want to check the PCM status to see if there is a later version that might have a bug fixed. L405 D350 SE Carpathian Grey D5 19" rims

I had exactly your phenomenon. It was an EGT-sensor that started to act up. It was gradually deviating and randomly reading a temperature that was too much off compared to the others, which triggered a plausibility check.

I think that it was really difficult to diagnose. If I remember correctly I think I needed to activate more Status Bit Flags for the IID than was on by default and also do the readout while the engine was running and the Restricted Performance light was on. It was really tough to catch it.

It came and went with very long intervals. When I managed to locate the problematic sensor, I exercised the connector and sprayed it with electronics spray. The fault stayed away for half a year and then returned. I resigned, bit the bullet, ordered a sensor and let my local Indie (Yes, I actually have one here in Sweden. Probably the only one in the country) change it as the sensor as normal had become an integral part of the exhaust system.

Now, 1,5 years later, I haven't seen it again so I would venture to say that the problem is solved

Graeme, that's a good call, thanks for your thoughts, much appreciated...

Dartanjang...

That sounds very plausible bearing in mind what my friendly tech said, I know it's not guaranteed to be the same one but which one of yours failed...?? Pete
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-Click here for Thread-
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
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2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
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For me it was Bank 1, Sensor 2. The easiest one to get to. A couple of threads about it:
https://www.fullfatrr.com/forum/topic65450.html
https://www.fullfatrr.com/forum/topic62630.html
I had the same fault code as in the second thread above, P2031-00

Another thread that helped me a bit:
https://www.fullfatrr.com/forum/topic50258.html

BR

Anders

Thanks a lot...  Pete
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2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
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Did you solve this Haylands?

A friend who is a JLR master tech comes back with this

I’d say it’ll likely be a corroded connection on an EGT sensor giving an implausible (but not excessively so) temperature reading, hence no DTC. The most likely one is the b’stard just after the exhaust branch, effectively under the drivers seat, I’d be checking the connector for corrosion and fretting. LR specify NyoGel 760G for filling the contact housings with, works a treat on EGT sensors and SRS connectors where there is low current but resistance sensitive connections being made… you could also check the live values of the various EGT sensors and look for one that is out of range of the others, being left to cool down suggests there’s an errant reading somewhere.

Dartanjang's experience fit's very well to that scenario....

Mine hasn't done it again and it needs to have the fault to be able to read the faulty sensor....

I've left it for now till it gets worse and is easier to find....  Pete
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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
-Click here for Thread-
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click here for Project Fatty off roader-

I know this is an old thread (I used the search) but mine did something similar this morning. I stopped the car pressed the stop button, engine ran on but did stop after a second or two. When I restarted the fault was gone and the car behaved perfectly, although I have the BT iiDTool in the car I couldn't used it as my iPhone was at home.

I'm thinking sod it just wait and see if it happens again, anyone got any ideas? Geoff

Geoff, seems one of those problems that needs to get worse before you can find which sensor it is... mines been behaving since...

You can buy the sensor with the longest lead, if fatty fails and you are stuck somewhere, you can plug in the new sensor and tie it to the exhaust with metal tie wraps as a get you home fix...!!!  Pete
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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
-Click here for Thread-
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click here for Project Fatty off roader-