My 97 XJR has been throwing the check engine light and giving me the P0400 code every couple of weeks so I decided to replace the EGR valve and clean the pipes thinking that would solve the problem.

About a week has gone by and she just threw the P0400 code again. Any ideas where I should be looking next to solve the problem? Thanks

 

Something from this forum

https://www.jaguarforums.com/forum/x...s-codes-78316/

 

Checked the air pump. Fuse is fine and pump was working when I felt it.

 

There was mention of a cracked or loose air hose air hose clamp in the thread . I myself have not looked to see exactly what they are talking about for I have no codes issues , just giving you a heads up .

Hope this helps , Parker

 

Here's the list of P0400 Possible Causes from the Jaguar DTC Summaries:



Graham

 

Based on the above Jaguar DTC Summaries provided probably the most least intrusive thing to do is to replace the EGR valve again on the basis of your previous replacement my be bad out of sock . The new one may be an intermittent failure and not a hard failure . Been there with bad parts . New EGR gasket wouldn't be a bad idea . Suggest also to clean up connector if it doesn't look good and a slight tug on the wires . I changed plenty of aircraft connectors after this test . Had a good pic on hose layout bud can't find it now but there was mention of the clamp on the hose ?

 

Did some digging as to the plumbing line routing and if you look at the aft most # 6 exhaust position you will see a bi fabricated line that comes out pointing straight back before it turns around the back of the engine . This is the EGR line . Mine is loose to the feel but that maybe because it is only a heat shield that is slid on covering the hot solid line inside . The line that is below the EGR as it goes around the corner is the secondary air pump line . There is a Y coupling underneath the exhaust manifold cover to split so there is a input into fwd and aft " banks ". Back around to the front of the engine at the secondary air pump the output line goes straight down along the position of the # 2 intake pipe . You will see a check valve . The condition of my hose at the secondary air pump is crushed and will probably cut off about an inch to get to a better conditioned section . I do not have any codes but I have other issues so I'm giving a hand . As to the relation between a secondary air pump and it's lines and a specific 400 EGR code I don't have a clue but that thread seams to point that there is a connection . For a good technical reference see page 54 ( continued )

 

Page 54 , 92 , 95 of the " subject " manual 801s - 2000

http://www.jagrepair.com/images/Trai...20-%202000.pdf

One recommendation from me is to look at the connector for the EGR temp sensor located between the EGR and the valve cover . One other thing to consider is the condition of the ECU connector in the cabin that has a history of water contamination from above skin gap under the wiper traugth . See page 23 of the electrical schematic as to the pin layout considering the pic is 180 degrees out as you look at the connector . Look at pins RED 3,5,7,12,14 and BLACK 31,35 . If you want to ring it out with a meter let me know . That was my profession .

Thanks , Parker

 

Oops , You're supercharged so your air pump is on the right side from mines left . But you should easily see the air pump check valve . The EGR temp sensor connector should still be on the left side between the EGR valve and the valve cover probably buried under the intercooler . Lady Penelope is N/A .

 

Thanks Lady Penelope. Looks like I have a few hours of detective work to do!