Hi Forum , I have a 2011 tdv8 4.4 which goes into restricted performance usually when started after stopping somewhere after a run .
I have a icarsoft reader which has thrown up P0486 egr circuit b high . Any ideas please .
Thanks Paul

The code P0486 indicates a "B" circuit malfunction, so check the EGR sensor connector for corrosion, bent or pushed out terminals or loose connection
There are many possible causes for this code. Some of the most common causes are:

Faulty EGR sensor “B”
Fault in the wiring harness to the sensor
EGR pintle stuck in the closed position causing carbon buildup, which keeps it from opening
Lack of vacuum to the EGR solenoid
Faulty EGR solenoid
Faulty EGR position sensor
Defective differential pressure feedback EGR sensor

Have you checked that the EGR is not clogged up? If it is it may hinder movement.

double post

Thank You Dolphinboy for the info , I think this might be a bit much for me to do , we do have a local Indy though .I also have P0404 which I've read about on here but it's been no problem for 2 years with me .

this may help.

https://www.fullfatrr.com/forum/post502792.html

useful info on the throttle body , i don't have any issues pulling away etc so i don't suspect any trouble with the body . Is it much of a job stripping the engine top down to get to the egr ? , i think the valve itself is probably sticking . I have cleaned the maf sensor housing as it was gunged up when i serviced the engine back in March .
I had a TD5 D2 before this RR , first thing i did with it was remove the egr but it's a different animal i have now .

Thanks for the help , much appreciated

The EGR valve can't get to be the same condition as the MAP sensor because there's no oil in the mix, only carbon. The muck that accumulates in the intake has oil from the turbos and carbon from the exhaust but the EGR valve only gets the carbon. However EGR valves can get stuck from just the carbon.

Thought I would share the outcome of my P0486 code issue . Having gone through the usual checks for air leaks etc and having found nothing wrong I bit the bullet and took it to Duckworths . . Initially nothing was reported as wrong , the Technician I spoke to noticed something slightly unusual with the sensor on the throttle body but in his opinion nothing to spark my code .
I decided to let them fit a new throttle body and do the P0404 sensor as it always bugged me.
1000 miles later not a problem , went to east coast yesterday , did 110 miles averaged 42 mph and returned 39.4 mpg , happy days .

I'm still a little apprehensive but it seems all good at moment . 2011 tdv8 4.4 vogue Santorini black

Do you mind me asking how much the throttle body was Paul?

not the first throttle body replacement I've read about.

Odd that the codes were saying otherwise.

Mind you, I had a code leading to turbo actuator, but was an air leak (feed pipe to the throttle body actually) so codes aren't absolute more a guide.

glad you got it sorted.

. Cheers, Greg
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2011 Vogue SE 4.4 with lots of toys in Stornaway

The throttle body was about £125 from memory , it's the labour and vat that spoils main dealer experience for me . I was very pleased with the technician at Duckworths though , they do love there Landrover's , showed me round workshops very impressive. 2011 tdv8 4.4 vogue Santorini black

I had a freelander which threw a EGR circuit B error a few years ago ... it also turned out to the throttle body.

That being said ... at the time, TOPIX did correctly suggest that circuit B error was in relation to the throttle body and not the EGR valve.


It seems backward, but I can understand some of the logic. When the EGR moves, the EGR system will likely consider the EGR position as the main circuit ( i.e. A ), and then it'll do secondary checks around the position of the throttle body ( i.e. circuit B) to manage the air pressures in the inlet manifold. Its likely also more prone to throwing errors as the throttle body position really matters to the proper operatation of the EGR feeding back exhaust gas into the inlet.

Raises the question why if the throttle body is failing and is throwing errors under an EGR heading, why does it not throw errors under a more general fuelling heading, or just a failing throttle body.

Only thing I can think of is that the fuelling system is far more tolerant of errant values given by the throttle body. The fuelling can also derive enough information from manifold pressure, air temp, air flow, fuel pressure, exhaust mixture, etc etc ... so it isn't tripping errors ???

Glad its sorted. V8 or else ...