Contour Enthusiasts Group Archives Forums General Troubleshooting EGR Problems

I have a 1999 Contour SE Sport with the V6. It's automatic with a/c and VIN code L. I got my first CEL the other day, code 401, insufficient EGR flow. I found the green vacuum line to the EGR had broken, so I repaired that and used the scan tool to reset the codes. I drove it for about 3 days and the same code came up again. I hooked up the computer and reved up the engine to where the pcm was calling for the EGR to open. I was getting vacuum to the line that hooks on the EGR. This told me that the solenoid is working ok and I have no further vacuum leaks (I also checked the other hoses). I either have a bad sensor, a seized EGR/broken diaphragm, tubing from exhaust or egr itself is stopped up with carbon, or one of the sensing tubes that connects the sensing unit to the EGR exhuast tube is plugged. I hope all that made sense. Is there any particular problem that seems most dominant? I've been warned to be careful about taking off the EGR as in loosening the exhaust tube, it can break off and then you got a real mess. I was unable to get it loose anyways as it's impossible to get a wrench due to the air intake box and the brake reservoir/booster. Any ideas are appreciated.

Clean the Throttle Body and do the EGR suck test.

TB cleaning
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EGR vacuum test.
Modified test for EGR (per Ray and Steve):
(remove the green vacuum hose from the top, be careful as it is brittle, and apply a vacuum (attached a small hose and suck on itl) to see if the car stumbles while running. This indicates a properly operating EGR.

Does it work properly?

NO: The EGR valve is defective or the EGR passages are clogged. Check (and clean, if needed) the passages behind the Throttle Body. Purchase a TB gasket, and remove the air plenum (rubber accordion tube) then remove the TB. Clean the EGR passage (small cut-out in the outer edge of the TB's mating surface) really well, install a new gasket and re-attach the TB. If the passages are clear, the EGR valve is defective. While rare, they do fail.

YES: The EGR valve works and the passages are clear. The likely fault is the DPFE sensor or its sample hoses, followed by the EVR solenoid or the PCM. May also be caused by interconnecting vacuum lines or electrical connections.

Actually, you should NOT have any vacumm to the EGR valve while the car is in your driveway. If you do, the EVR solenoid is passing air when it should not.

Steve

I wasn't getting vacuum when it was just idling. If I revved it up and created the right conditions, then it would start to pull vacuum. I watched the snap-on tool we have to make sure it was calling for the egr to open, and it would only create a vacuum when the computer was calling for it. I haven't had a chance to do the vacuum test manually yet, but I'll relay the results. In the mean time the stupid light has gone out again so who knows.