so I got a p0400 code then I replaced the egr valve with a used one from a 58k mileage XJR. Mine has 89k. After around 12 miles of driving CEL came on again with the same p0400 code. What did I missed here? I just recently filled up the gas tank to the brim, has that anything to do with egr valves? Thanks.

 

Did you check in the pipes for any buildup? Check the electrical connection for the relay and the rubber tubing for any cracks. Did you replace the gaskets on the rigid tubing from the exhaust manifold to the unit? Usually they are able to be put back on, but if they are dinged or brittle, they will leak.

 

That accordion pipe wrapped in insulation is fragile and could be cracked. It's also very expensive.

 

What year is yours maniqz? ....mine is a 2000 and doesn't have the wrap that RJ237 speaks of. Just want to be sure we're giving you the correct info.

 

When you replaced the EGR, did you check and make sure that the passageway was clear of carbon going inside the throttlebody elbow?

highhorse: mine is a 98' and I have the protective sheathing on the EGR tube. If you don't have one, I'd recommend you put some kind of heat protective wrap on.

 

Mine didn't come with one, I don't know if it makes a difference, but mine is S/C'd.

 

To the best of my knowledge concerning EGR and USA X308's, only XJR's have them. I know the 97' and/or 98' XK8's N/A had EGR but then got a delete plate and software reflash. I think these XK's were destined for the USA and once they got here they had the plate and reflash done. I don't remember if the 98' XJ8 got a delete plate and reflash. I know there's a TSB concerning this for the XK8's. Anyways, mine is also an XJR so it does have the protective sheathing on my EGR pipe, I'm pretty sure the reason for the sheathing is because the EGR pipe is thin metal and that a higher temperature of heat can disapate from that pipe onto the engine wiring harness that's just above it. Think of it this way... on our XJR's the bank one catalytic convertor has a silver, fiberglass (ish) heat shield between the cat and transmission. Well, behind that heat shield is the transmission wiring harness. It was just a means of protecting the wiring from excessive heat.

 

Thanks everyone for all your help, always grateful for this website and it's helpful people. I will take note of all these and go through them after this busy holidays. So right now I am just resetting the codes twice now.
Highorse, mine is a 2002 but I'll check if I have that insulation.

 

Took a peek today and took this pic. Tried to check the wires, they seem fine. But I'll dig deeper next time