98quiksilvergt Posted December 27, 2009 Share Posted December 27, 2009 Got cel code tonight. P0400. Egr flow malfunction. Any ideas? Link to comment Share on other sites More sharing options...
gathermewool Posted December 27, 2009 Share Posted December 27, 2009 oh, I've got ideas! haha I battled this bad boy for over a year. 1. Open the hood and, with the engine still cold, operate the throttle to rev the engine. Observe the EGR valve. It should NOT open when the engine is cold. If it does, it could be the EGR solenoid sticking open. To check, unplug the EGR solenoid and repeat step 1. The EGR solenoid should remain deenergized shut while disconnected, making it impossible for the EGR valve to open. The only way for it to open unplugged is if it's stuck open. 2. When you get home after a drive - the engine warmed up - repeat step one. The EGR valve should open briefly then shut. If it does not open at all, do the following: - Inspect all of the vacuum lines that you see associated with the system. If any/all are suspect replace them; very cheap and easy to do. Repeat step 2. 3. If the valve opens and seems to work properly, but the code persists perform the following: - With your finger, manually open the EGR valve. The engine should bog down considerably and nearly stall, then recover. If it doesn't, order a new EGR valve gasket. Remove the EGR valve and gently clean it. Clean the EGR tubing as well. This should clear the passages and allow sufficient flow. 4. If none of this works, you'll need to buy a vacuum pump to further test the system. Apply vacuum to the dome of the EGR valve and see if the vacuum bleeds, indicating a hole in the EGR valve diaphragm. I'm too tired now, so try these and we'll keep working on it tomorrow : ) '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
98quiksilvergt Posted December 27, 2009 Author Share Posted December 27, 2009 Ok, I'll get back to you Sunday evening. I have to work all day until 7 pm. I'll try it before I leave when it's cold, then when I get home. Thanks alot!! Link to comment Share on other sites More sharing options...
gathermewool Posted December 27, 2009 Share Posted December 27, 2009 Sounds good, and gl. Just make sure not to throw parts at this. Cleaning and replacing vacuum lines is much cheaper and sometimes works. For me, it ended up being the solenoid valve being stuck open. Also after replacing the EGR line (mine was leaking badly at the fitting) and cleaning the EGR valve the motor would more noticeably bog down, so I'm sure that helped as well. '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
98quiksilvergt Posted December 28, 2009 Author Share Posted December 28, 2009 I couldn't check it cold. I just checked it warm and if I blip the throttle it opens a little then closes real quick. If I give it a good rev it does the same thing. It doesn't stay open. I'm going to get a bunch of vac. Line tonarrow from work and just change all the lines I can. Link to comment Share on other sites More sharing options...
gathermewool Posted December 28, 2009 Share Posted December 28, 2009 Did you try opening the valve with your finger while at idle to see how much it bogs down? Pull the plug on the solenoid, too to see if it still opens '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
98quiksilvergt Posted December 28, 2009 Author Share Posted December 28, 2009 Yeah, it bogged alot. Almost stalled. Link to comment Share on other sites More sharing options...
gathermewool Posted December 29, 2009 Share Posted December 29, 2009 don't forget to unplug the solenoid. It's a quick, easy check to see if the solenoid is mechanically stuck open. If you unplug it and the EGR valve opens when you blip the throttle replace the solenoid. '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
98quiksilvergt Posted January 11, 2010 Author Share Posted January 11, 2010 Well... I pulled the vac line off the egr valve and drove it for a day with it plugged. Then hooked that back up and unplugged the disc thing obove the egr for a day. Hooked it back up and drove it for two days and the code cleared itself. Cel has not been on for a week now. Link to comment Share on other sites More sharing options...
gathermewool Posted January 11, 2010 Share Posted January 11, 2010 Well... I pulled the vac line off the egr valve and drove it for a day with it plugged. Then hooked that back up and unplugged the disc thing obove the egr for a day. Hooked it back up and drove it for two days and the code cleared itself. Cel has not been on for a week now. The disc thing I think you're referring to is called the Back Pressure Transducer (BPT) It controls the amount of vacuum applied to the top of the EGR valve diaphragm based on the vacuum differential across the throttle plate, and the exhaust backpressure. There are two vacuum lines coming in on the passenger side of the "disc," one on the driver's side, and a larger diameter, shorter piece on the bottom, right? If all you did was detach and reattach the vacuum tubing, I'm afraid your problem isn't gone for good, my friend. It may be a day, maybe a month, but it will most assuredly come back. When mine first reared it's ugly head it would only come on during cold starts, then clear itself during the next highway trip or over an extended period of driving. Eventually, the code remained in, and would come in every single time after being cleared. This, for my case, was due to the solenoid slowly degrading until it finally completely failed open, always allowing vacuum to open the EGR valve, even if the ECU was saying, "no, don't do it!" '15 FB25 Magnatec 0W-20 + FU filter (70,517 miles) RSB, Fr. Strut Bar, Tint, STI BBS, LED er'where Link to comment Share on other sites More sharing options...
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