03 4.2 XJR- EGR fault code P0400

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naki
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Location: Kirton, nr Boston, Lincs, UK.

03 4.2 XJR- EGR fault code P0400

Postby naki » Sat Jan 27, 2018 1:19 am

03 4.2 XJR- EGR fault code P0400

I had this CEL/ fault code appear recently about 90 miles into a motorway journey. The car appears to run as normal with no other obvious symptoms. I cleared the code and carried on. It returned about another 90-100 miles later.

My initial thoughts on anything to do with EGR, is it could be blocked/ restricted, though i am not sure if thats more common on diesels than petrols? I have done some other reading elsewhere, but most of the posts are for the 2.7 diesels, or the earlier 4.0 engines, and the suggestions seem varied and inconclusive. i guess there could well be more than one issue that could raise this fault. So any thoughts on where to start first?
Usually the easiest checks/ clean out valve approach i would imagine?
Also being new to this model, i do not even know where the valve is. Any pointers much appreciated, before i start poking around.

Previous work done- I renewed the thermostat, which went without a hitch (unless this could be related in any way- unlikely?).
i was going to change the Coolant temp sensor at the same time, but the dealer provided the wrong one, twice, despite having the VIN!
Last edited by naki on Tue Jan 30, 2018 8:22 pm, edited 1 time in total.
91 4.0 XJ6 Manual
92 4.0 XJR Manual
93 3.2S-4.0S Man conv
93 4.0 Sov
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 X306 4.0 XJR
96 X300 Daimler Six LWB
97 X300 Sport 4.0 Manual
00 LR Discovery 2 TD5 ES A
03 X350 4.2 XJR
BREAKING various X300/ XJ40/ X308

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J44EAG
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Location: Warlingham Surrey/Faversham Kent

Re: 03 4.2 XJR- EGR fault code P0400

Postby J44EAG » Sat Jan 27, 2018 2:41 am

Hi Naki,

Yes, the EGR valve can cause issues. I replaced mine when I had the charger off for porting and polishing and also changed the charger drive coupling and the oil together with the notorious and inaccessible valley pipe.

The valve is prone to oil/carbon contamination at higher mileages. It is electronically controlled with a socket on the unit. You might exercise the plug to clear any possible corrosion. You have to remove the air expansion plenum above the throttle body to get to it. Use an 8mm socket on a flexi drive to get the Jubilee clip undone around the plenum exit to gain access. Getting the EGR valve off is a bit of a nightmare due to little working space to the left of the throttle (Off side) I recall it is held onto the throttle body elbow by two long 5mm bolts. It took me half an hour to get those out due to space constrictions. There are also a couple of coolant pipes linked to the valve. The are crimped to the valve with gas crimps. I had to hack saw those off which was nasty. You will need a couple of stainless Jubilee clips to replace them.

Then the going gets really tough. I recall a couple more bolts UNDERNEATH the valve which join it to the solid and very immovable stainless pipe which links to the OS exhaust manifold. Again those bolts are not easy to access. Getting the pipe off the manifold is also a PITA. If you must have the EGR valve off, then also get the two crush gaskets as well. If you have got that far, then the chances are you will have removed the throttle body as well. Again a crush gasket is below the throttle body and sits between that and the elbow. Having the throttle off means you can clean out the gunk in the throat which can get very heavily contaminated. On the back of the elbow lives the MAP sensor. Two screws or bolts hold that in place. That sensor will be knees deep in grunge. Get that nice and clean and clear out the gunge within the channel on the elbow. You will also find the elbow caked with muck. A big puddle of solid gunk will be found at the lowest point.

Halfords sell EGR valve cleaner which you can squirt into the air intake. I didn`t find that very helpful though. The whole intake below the throttle can get in a real mess. I resolved not to have those issues again so installed my water/methanol system which cleans carbon and oil most effectively off the above parts as I drive. Its like mobile steam cleaning.

If EGR cleaner doesn`t work, you might try the poor mans version of water/methanol injection....namely using a spray bottle and water. Set up a fast idle and spend the next hour spraying water as a fine mist into the intake to the right of the MAF sensor on the air box lid. Keep the spray off the MAF. Water spray is very effective at gunk removal. Go to the exhaust tips and watch water drips depositing carbon on the ground. You will be surprized how much accumulates.

Getting that valve off defeated me. I`ve a collapsed lower lumbar, sciatica in my right leg and am prone to cramping if assuming the wrong position. You will have to climb on top of the engine to get that damned valve off. It is a positively evil job....one of the worst ones I`ve ever come across. I ended up with the car on a recovery truck and was literally shaking with exhaustion by the time the valve removal defeated me. I ended up subbing the job out to Jagcare in Portsmouth. I reached my limit and had to concede defeat.

I`d like to have got the result myself and to have been able to be more encouraging as to the nature of that job. Unfortunately, I can`t be!

That CHT sensor always gets the Parts Man. They tend to order the oil pressure light switch. Thats rather fatter than the CHT sensor. Always get genuine OE for these and other sensors on the car. One duff and hopeless part off eBay taught me that. See my thread on the sensor in the coolant section. I wrote an article for the magazine within the last two years which will help you. See "The nineteen day glitch!" which deals with some of these issues. Also get a length of rubber 3.3mm ID vac/pressure pipe from Jaguar or better still Halfords. Frankly, the Halfords pipe is tougher and rather thicker. Replace the pipe off the by-pass actuator to throttle elbow and from the cowhorn charger pressure manifold whilst you have the car in bits. Its a no brainer to ignore it. Those little pipes rot for a past time.

The XJR is a great car but expect the parts around the throttle body to suffer advanced decay due to heat, oil/carbon contamination and lack of maintenance. Non of this work figures on service sheets. Regret to say this is the XJR/XKR`s biggest and most difficult weak spot.

Give me a call if you need further help.

Mike
X350 Co-ordinator

2004 XJR

naki
Posts: 392
Joined: Thu Aug 30, 2012 12:28 pm
Location: Kirton, nr Boston, Lincs, UK.

Re: 03 4.2 XJR- EGR fault code P0400

Postby naki » Sun Jan 28, 2018 12:02 am

Thanks for the detail reply Mike. I might have known it was not going to be simple (it’s a jag.....).

Something puzzled me. I had heard that when EGR valves give issues, there tends to be recognisable symptoms like poor running, rough idle etc. Though I imagine the symptoms can be incremental?
Now here’s the crunch point. Should I not drive the car at all until this is fixed? Clearly I don’t want to cause a further issue/ break down etc.
It also odd how it takes a 100 miles for the fault/ CEL to show up. Does mean that the valve is only just out of range, as opposed to totally clogged?
I am just trying to interpret exactly what the situation is.

I will have a go at the repair myself, and see how I get on. Stretcher at the ready though?
Though no idea when I will get around to it if it is a big job.

I note you replaced yours with a brand new part? Though I assumed it would be possible to clean out the existing part (with carb cleaner etc).
I am going to look up the new part just see but I am expecting it up be silly money invariably?
Genuine?

Noted on the hoses/ fixings etc.
91 4.0 XJ6 Manual
92 4.0 XJR Manual
93 3.2S-4.0S Man conv
93 4.0 Sov
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 X306 4.0 XJR
96 X300 Daimler Six LWB
97 X300 Sport 4.0 Manual
00 LR Discovery 2 TD5 ES A
03 X350 4.2 XJR
BREAKING various X300/ XJ40/ X308

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J44EAG
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Re: 03 4.2 XJR- EGR fault code P0400

Postby J44EAG » Sun Jan 28, 2018 1:05 am

I`ve sent Naki a couple of previous magazine articles in regard to what he can expect to encounter. If anyone finds themselves about to attempt repairs from the throttle body, EGR valve, by-pass actuator, MAP sensor etc through to removal of the supercharger for overhaul, porting or super small 10% pulley fitting or to gain access to the valley heater return pipe in the centre of the V, please contact me via the 350 email address and I`ll send you the text or possibly a PDF detailing what is required.

I replaced my EGR valve, Naki, because the top section flew off in my hand and an internal spring fired off across the yard, never to be seen again! I sourced a new valve by typing in the part number into a search engine. I was fortunate to find one at around 25% cheaper than anywhere else on the net. I recall the normal cost totals around £160. The internals of the valve although well carboned up appeared in reasonable condition and moving relatively well. It was functioning to my knowledge before I began stripping the job down. Had it not fallen to bits, I`d have cleaned it out with petrol and put it back on the car. I was just unlucky on this occasion.

Your part Naki, may just be coked up and need cleaning. The trouble is that its a lot of repeat work to remove that unit again and fit a new one if the old part fails to respond to a clean. I`m not sure how the valve gets its driver signal other than from the ECU or what causes it to operate....presumably when the throttle plate is closed on, say, down hill over-run and partial vacuum exists in the charger elbow under the throttle plate. That vac also pulls on the by-pass capsule which opens the by-pass flap to spill unwanted excess charger pressure. (Essentially a dump valve which depressurizes the cowhorn distribution pressure manifold.) If in doubt about the valve, replace new or contact Eurojag whom I understand sell reconditioned items. Try the Halfords EGR spray cleaner before changing the valve. Perhaps blast a couple of cans in through the charge air inlet pipe by removing the lid of the air cleaner box. You might be lucky and clear the issue.

Many cars will run with a removed EGR valve and a blanking plate fitted. ie the 2.2D X-type/Mondaeo engine where the conversion appears to be possible. One of my Jag contacts in Portsmouth told me he considered the XJR valve un-necessary. I can`t confirm that though as I`ve heard nothing else that suggests blanking may be possible. Personally, I can`t see why you shouldn`t continue to use the car until you get around to fixing it. Sure, its a nause to have to keep cancelling the fault code and a groan to keep seeing the MIL lamp or engine check light on the dash. Orange lamps in this respect are cautionary advice, where as a red lamp means stop the car immediately. The MIL, I believe only illuminates after three consecutive electronic events have occurred, so the faulting might have occurred on two other separate occasions before the lamp eventually pops on.

As we know, these supercharged models can take some keeping up with as mileage accumulates. Many parts fail from around 90k. Front wheel bearings, suspension bushes, tubes and pipes, charger and heater pumps, etc, etc. Most of those items are not on the normal service schedule. That`s just a bit of oil servicing, a brake check and that`s pretty much it. It is all the out of schedule servicing items that can often spoil the fun. The charger adds a fair amount of complexity to a 4.2R lump. They are great when problem free but sometimes a tear jerker when maintenance has to be done. If only there were more space at the back of the engine. Then it would not be a big deal.

Mike
X350 Co-ordinator

2004 XJR

naki
Posts: 392
Joined: Thu Aug 30, 2012 12:28 pm
Location: Kirton, nr Boston, Lincs, UK.

Re: 03 4.2 XJR- EGR fault code P0400

Postby naki » Sun Jan 28, 2018 8:47 pm

Cheers Mike. Plenty of things to think about there.
I would be happy to blank off the EGR, if it was a proven modification. With positive results.
I have a Discovery 2 TD5, and it’s a common mod on those, and other diesels I imagine too.

I am not doing enough miles in this car to really monitor it accurately, and since the light does not come on before 90 miles driving, currently, it’s going to be hard to asses of the EGR spray cleaner, has worked, it’s an option though.

I will let you know how I get on.
91 4.0 XJ6 Manual
92 4.0 XJR Manual
93 3.2S-4.0S Man conv
93 4.0 Sov
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 X306 4.0 XJR
96 X300 Daimler Six LWB
97 X300 Sport 4.0 Manual
00 LR Discovery 2 TD5 ES A
03 X350 4.2 XJR
BREAKING various X300/ XJ40/ X308

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J44EAG
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Joined: Sat Oct 20, 2007 9:57 pm
Location: Warlingham Surrey/Faversham Kent

Re: 03 4.2 XJR- EGR fault code P0400

Postby J44EAG » Sun Jan 28, 2018 9:02 pm

The EGR valve cleaner is a good old Wynns product so should be easily available in motoring stores or on Fleabay. Here is the Halfords link. Around 25% off if you are lucky enough to have a trade card.https://www.google.co.uk/url?sa=t&rct=j ... eb3kJ_X23n

Although this ad is for a diesel valve cleaner, I bought the petrol version. I can`t imagine there can be much difference. Carbon clag is much the same whether petrol or diesel.

Mike
X350 Co-ordinator

2004 XJR

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J44EAG
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Re: 03 4.2 XJR- EGR fault code P0400

Postby J44EAG » Mon Jan 29, 2018 5:34 am

You could install a copy of my water/methanol system, Naki!

That would certainly help de-gunk the MAP, sensor, the charger elbow, the throttle throat and the EGR valve! The system really does help keep all these critical components clean and free of oil and carbon contamination. That even extends to the inlet valves and the piston crowns. Here is the link to my installation.
viewtopic.php?f=281&t=10887&hilit=methanol+injection

Mike
X350 Co-ordinator

2004 XJR

naki
Posts: 392
Joined: Thu Aug 30, 2012 12:28 pm
Location: Kirton, nr Boston, Lincs, UK.

Re: 03 4.2 XJR- EGR fault code P0400

Postby naki » Tue Jan 30, 2018 8:25 pm

Thanks Mike. Sounds like a good idea.
Limited time at the moment, so I am unlikely to start pulling things to bits at the moment.
Plus I may need to do a long trip in the car on Friday.
It may even wait until spring is here. Will see.

When you did your Terraclean, do you think it cleaned the EGR too?
91 4.0 XJ6 Manual
92 4.0 XJR Manual
93 3.2S-4.0S Man conv
93 4.0 Sov
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 X306 4.0 XJR
96 X300 Daimler Six LWB
97 X300 Sport 4.0 Manual
00 LR Discovery 2 TD5 ES A
03 X350 4.2 XJR
BREAKING various X300/ XJ40/ X308

User avatar
J44EAG
Posts: 5604
Joined: Sat Oct 20, 2007 9:57 pm
Location: Warlingham Surrey/Faversham Kent

Re: 03 4.2 XJR- EGR fault code P0400

Postby J44EAG » Tue Jan 30, 2018 8:44 pm

The Terraclean process can`t clean the EGR valve, Naki.

Terraclean is essentially just a highly effective in situe injector and combustion clean process only. ie "mid" engine clean up.

The only possible cleaning of the EGR valve without manual intervention are water spraying via the outlet into the inlet trunking through the lid of the air cleaner box or fitting water injection. Wynns EGR valve cleaner may or may not help the issue. That tackles the "top" engine cleaning.

The "bottom" end of the engine cleaning is best tackled in my own personal experience by using an oil flush additive immediately prior to an oil and filter change. EDT treatment can effect further clearance of combustion by-products.

Using Cataclean or Oxy Cat in the fuel could conceivably also touch the EGR valve which can foul up due to carbon pulled through it from the OS exhaust manifold. Both products (I prefer Oxy Cat which appears very effective with the cats) claim to clean Lambda sensors and the cats. On the basis of that, trying either of those products might produce a result for you. I`d try a concerted couple of sessions with gentle water spraying at the inlet trunking and also dump a couple of Oxy Cat cans in the fuel tank.

See how you get on.

Mike
X350 Co-ordinator

2004 XJR

naki
Posts: 392
Joined: Thu Aug 30, 2012 12:28 pm
Location: Kirton, nr Boston, Lincs, UK.

Re: 03 4.2 XJR- EGR fault code P0400

Postby naki » Tue Jan 30, 2018 10:46 pm

good stuff Mike. Plenty of great info there.
Shame theres no time to act upon any of it at the moment.
i will report back with any progress in due course.
91 4.0 XJ6 Manual
92 4.0 XJR Manual
93 3.2S-4.0S Man conv
93 4.0 Sov
93 6.0 XJ81 DD6
93 6.0 XJ81 XJ12
94 4.0 XJR
96 X306 4.0 XJR
96 X300 Daimler Six LWB
97 X300 Sport 4.0 Manual
00 LR Discovery 2 TD5 ES A
03 X350 4.2 XJR
BREAKING various X300/ XJ40/ X308


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