My 2001 XG just started running roughly the other day. I got cylinder misfire & EGR malfunction fault codes. I have replaced all 6 spark plugs and then yesterday replaced the EGR valve. The car is still running rough. I sprayed MAF cleaner in the MAF and the throttle body. Now I'm getting a new code: P0403 which is EGR circuit flow malfunction.

From what I've found, there isn't an EGR solenoid on the XG so I"m at a loss of where to go from here.

Someone suggested replacing the O2 sensor - but I don't think that's necessary since I believe there is a separate fault code for that fault. The MAF was replaced a few years ago - under warranty and appears to be clean and free of buildup.

Any help would be greatly appreciated in trying to track down this problem.

Thanks,
m

My own update: There is indeed an EGR solenoid on a 2001 XG300. It is on the back of the manifold held in place by a bracket and vacuum tubes just to the left of the orange/redish Vacuum Control Valve. See the TSB on the EGR for more information on diagnosis of the EGR system. Code 0403 is obviously the circuit flow malfunction. The only thing I have left to test/replace is the solenoid, so I"ll update on after I'm done.

Thanks for the update, it's very useful to the forum to have closure of a thread for buildup the knowledge base. Let us know how it works out.

Will do. Dealer has the solenoid in stock for $41. PIcking it up this afternoon.

===Edit===

I bought the solenoid and installed it. Some change, but not back to perfect yet. I followed the TSB to determine I do *not* have a vaccuum leak. So, I'm at a loss now.

For what it's worth, the service manager told me "I have those in stock (the EGR solenoid) because they always fail in that car." So, heads up to anyone facing the same problem.

The TSB says now that if I'm still getting 0403, I need to check the ECM (eek! $400).

I will update after the weekend to let ya'll know of any progress.
m

This post has been edited by seagull: Oct 15 2009, 01:05 PM

I would suggest that you clear the ecm memory so it doesn't show the code- take off one of the battery terminal clips then get in the car keep the vehicle switched off and keep tapping the brake pedal for a couple of min then refit the terminal -restart the car and the ecm should be clear.

Cheers

Itza

I did that yesterday afternoon. The code cleared, car still ran like crap. When I got home I tested the pcv valve, so that's not it either. The MIL just came back on so I'm going to get the code(s) off of it and see what it's saying. I'm also just going to go ahead and replace all the vacuum hoses just for the **** of it to rule that out completely.

I don't know if I said this in my original post or not. but the pipe that the EGR valve connects to. --- the dealership cross threaded the bolt that goes onto the egr valve. so the new EGR valve is on there..tight...but isn't completely seated down on the pipe....any idea how badly that would affect my performance here? I would think the code I'd be getting was more EGR flow insufficient or malfunctioning (like 0401)...not the 0403 circuit malfunction code I'm getting.

ok, i'm chiming in here one more time because I see your about to make a mistake. Dont touch those vacuum lines as some of them have restrictors in them. If you allready replaced the solenoid and try'd removing the vacuum hose from the EGR valve to improve the idle and succeeded then go ahead and replace the vacuum control valve that's linked to all those vacuum lines. it's supposed to bleed off vacuum at 7 in of vacuum. If it does'nt and all ~20 in of vacuum are going to the egr then the solenoid may not be able to bypass that vacuum back to the engine. Try that and if all this does'nt work time to remove the intake and look for crud inside the EGR valve. (IMG:http://hmaservice.com/files/331/1097529/0136021a2.jpg)

I didn't replace *all* of the lines, just the one from the EGR valve to the vacuum control valve and the one at the top-left of the vaccum control valve to the egr solenoid - why those two? Well, they were both the crappiest of the lot and while I couldn't feel a crack, they were in bad shape so I replaced them just for good measure.

That being said, the car runs a LOT better, but I'm still getting poor idle's at stop lights, after the car has been driven. I'm going to pull the code this afternoon and see what it's telling me now.

Do you have any suggestions/input about what I said earlier about the cross threaded bolt on the pipe from the EGR valve and the new EGR valve not being "seated" on the pipe - but being as tight as I could get it without stripping this new EGR valve? The pipe is only $50, but if that's not an issue, then I'm not spending the $50 (IMG:style_emoticons/default/smile.gif)

Thanks,

I would still try replacing the control valve. As for the cross thread, if it's leaking from there then it would cause an exhaust leak but not a rough idle. You can feel for a leak with your hand after a cold start so to not burn yourself when everything is hot. Just manuever your hand around the connection and feel for air leakage. If you replace the pipe then you have a crossthreaded egr opening. So now you need both or maybe just the valve as the threads are a harder material then the alluminum.