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Engine, Exhaust, Transmission and DifferentialPost questions here that have to do with the engine, cooling system, air intake, exhaust, Transmission and Differential
How many miles on the car? THat code is most usually an indication of little or no flow. WHat did the passages look like when you change the valve?
Is there 12 volts on one pin? If the ECU is telling it to open, you will have 12 volts on one side and zero on the other. IF you have zero on both sides, the B+ feed to it is not there, ya gotta fix that.
If you have 12 on both sides, you have good power but the ECU (at that particular time) is not asking it to open.
Thanks for the reply.
I'm at 119,000 miles.
The passages were dirty but nowhere near being clogged. I cleaned them out before reassembly.
I haven't measured any voltages yet. From the manual, pin 2 is connected to the RCM (should be 12V at all times, I assume) and pin 1 is connected to the PCM. I assume that pin 1 would go to ground to activate the solenoid. Is this correct? I have no idea how to know when it would be set to be open (when the EGR valve was active or not).
I'll verify that pin 2 has 12V. Meanwhile, what is the B+ feed?
Thank you!
Pg 9350, P0400 EGR system performance, diagnostics
B+ is the feed from the battery thru the Engine Control relay on the RCM. You will have battery voltage anytime the key is "ON". And yes, the PCM pulls pin7/1 to ground to activate the EGR valve; that is, to open the valve and allow exhaust gas to pass thru to the intake.
Every time I read a post, I freak out and look under the bonnet. My 2006 N/A XF seems to be in very good condition, and the guy that sold it to me had been careful with this unit, as whenever I check "critical points" due to your sound suggestions, I find the parts to be OK.
I decided to remove the EGR to see how clogged it was and its overall state. I didn't find much info on how to actually disassemble it, so here is my little guide for mechanic noobs like myself.
I found an old post (2008) by TVT_DESIGN where they delivered some instructions. That helped... "The EGR valve is on the passenger side of the back of the engine. They are known to become clogged over time.
Two bolts remove the top from the manifold, and two more on the engine block itself. Unclip the yellow connector, then remove the MAF and intake elbow to give yourself some room. Wiggle the EGR out of the manifold, it bends so it comes out but takes some time. Clean off the tube that was in the manifold making sure there is no gunk left in it. Reinstall, reset ECU, and you should be ok."
Please find this explanation along some comments below, together with some pics to make it a bit easier.
This is a pic of the EGR when you remove the beauty cover of the engine. Remove the black big rubber hose on top.
Two bolts remove the top from the manifold. The one on the right is a bit askew, but the ratchet will get in there. These two next to the copper screw...
And two more on the engine block itself that hold the metal pipe that goes in there. Pay attention to the metal gasket when you remove the pipe -you do not want to lose it inside the engine.
Unclip the yellow connector and spray it with some electronics contact cleaner, Nothing else is yellow, so pinch the metal plugs, pull and wiggle softly. Please notice the new ground cable (negative to engine) I installed a while back at the bottom of the pic.
Then, remove the MAF and intake elbow to give yourself some room. Remove the rubber tube that goes into the manifold. Pinch it with your fingers and pull gently. It should come out easily.
Wiggle the EGR out of the manifold. Be gentle and careful with the metal gasket that joins it to the engine block. What I did:
After removing ALL bolts, I bent the EGR a bit to access the EGR pipe screw union.
Used a 22mm wrench to unscrew the pipe from the EGR itself (be gentle, the pipe bends, but do not overdo it. It can be broken easy).
removed the EGR.
Then "played" with the pipe itself. It goes deep inside the intake, and it is not straight. That is why you need to remove the MAF and elbow down to the throttle body. Pull and bend gently and it'll come out. Clean off the metal tube that was in the manifold, making sure there is no gunk left in it. That's the dirtiest part I found in mine.
I then cleaned the EGR and metallic pipe (outside and inside, using a decarboniser product) paying attention not to spray on the vacuum pump itself, the round part at the top -it's a rubber piece underneath, we would not want to ruin it. I also checked that the small rubber hoses were flexible and not cracked. They might not hold the vacuum instead. To tell you the truth, all seemed to be OK, with no clogging at all.
I then reverse-engineered all procedures, reinstalled, reset ECU, that was it.
Every time I read a post, I freak out and look under the bonnet. My 2006 unit seems to be in very good condition, and the guy that sold it to me had been careful with this unit, as whenever I check "critical points" due to your sound suggestions, I find the parts to be OK.
I decided to remove the EGR to see how clogged it was and its overall state. I didn't find much info on how to actually disassemble it, so here is my little guide for mechanic noobs like myself.
I found an old post (2008) by TVT_DESIGN where they delivered some instructions. That helped... "The EGR valve is on the passenger side of the back of the engine. They are known to become clogged over time.
Two bolts remove the top from the manifold, and two more on the engine block itself. Unclip the yellow connector, then remove the MAF and intake elbow to give yourself some room. Wiggle the EGR out of the manifold, it bends so it comes out but takes some time. Clean off the tube that was in the manifold making sure there is no gunk left in it. Reinstall, reset ECU, and you should be ok."
Please find this explanation together with some comments below, together with some pics to make it a bit easier.
This is a pic of the EGR when you remove the beauty cap of the engine. Remove the black big rubber hose on top.
Two bolts remove the top from the manifold. The one on the right is a bit askew, but the ratchet will get in there.
These two next to the copper screw...
And two more on the engine block itself that hold the metal pipe that goes in there. Pay attention to the metal gasket when you remove the pipe -you do not want to lose it inside the engine.
Unclip the yellow connector and spray it with some electronics contact cleaner,
Nothing else is yellow, so pinch the metal plugs, pull and wiggle softly. Please notice the new ground cable (negative to engine) I installed a while back at the bottom of the pic.
Then, remove the MAF and intake elbow to give yourself some room. Remove the rubber tube that goes into the manifold.
Pinch it with your fingers and pull gently. It should come out easily.
Wiggle the EGR out of the manifold. Be gentle and careful with the metal gasket that joins it to the engine block. What I did:
After removing ALL bolts, I bent the EGR a bit to access the EGR pipe screw union.
Used a 22mm wrench to unscrew the pipe from the EGR itself (be gentle, the pipe bends, but do not overdo it. It can be broken easy).
removed the EGR.
Then "played" with the pipe itself. It goes deep inside the intake, and it is not straight. That is why you need to remove the MAF and elbow down to the throttle body. Pull and bend gently and it'll come out. Clean off the metal tube that was in the manifold, making sure there is no gunk left in it. That's the dirties part I found in mine.
I then cleaned the EGR and metallic pipe (outside and inside, using a decarboniser product) paying attention not to spray on the vacuum pump itself, the round part at the top -it's a rubber piece underneath, we would not want to ruin it. I also checked that the small rubber hoses were flexible and not cracked. They might not hold the vacuum instead. To tell you the truth, all seemed to be OK, with no clogging at all.
I then reverse-engineered all procedures, reinstalled, reset ECU, that was it.
Re: P0400 Help Needed
My 2006 N/A XF seems to be in very good condition, and the guy that sold it to me had been careful with this unit, as whenever I check "critical points" due to your sound suggestions, I find the parts to be OK.
