2000 Protégé Code P0401 – EGR swap? - Mazda Forum - Mazda Enthusiast Forums

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Old 12-29-2010, 06:13 PM
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Default 2000 Protégé Code P0401 – EGR swap?

Just as I was about to sell the car, my 2000 Protégé LX 1.8L with 200,000km started throwing code P0401 (Insufficient EGR flow). Every time I clear the code, it happens again within about 20kms, usually on deceleration. Other than the CEL, the car seems to be working fine – no idle issues, no increased fuel consumption.

I removed the EGR valve and found that there wasn’t that much carbon build-up. The spring and valve seemed to function perfectly. I also tested the resistance between pins (as specified in my Haynes manual), and everything tests correctly. I cleaned out the EGR valve as much as possible and re-mounted it. It threw a P0401 CEL within 20km as usual.

I brought it to a garage today and he basically said that 95% of the time, it’s the EGR valve. He checked the vacuum lines, and everything tested OK. He wants $150 + 1.5hours labor to replace the EGR valve with one of the newer versions that have coolant running through them. Coincidentally, the older EGR valves like mine are closer to $200.

I’ve read on too many forums, people changing their EGR valves, and still throwing code P0401. Remember, I’m selling the car. The mechanic said that he could run more definitive tests, but that would cost me 3 hours labour at $60/hr.

That being said, I also have a 2002 Protégé 5 2.0L whose EGR valve requires cleaning every 6 months or so. That one gets so dirty over that period that the spring and valve stay in the open position resulting in low rpm hiccups at stoplights. No CEL though. By now I’m at expert at taking that EGR valve off, so I thought that I could use it to troubleshoot the other car.

I would appreciate it if someone could tell me if my 2002 Protégé 5 2.0L EGR valve will fit/function correctly on my 2000 Protégé LX 1.8L.

If it doesn’t, are there any recommendations as to what I could do to get this car in selling condition without breaking the bank. Maybe get a junkyard EGR valve to test? Change all vacuum hoses just in case? MAF sensor?

Thanks for your time.
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Old 01-02-2011, 12:06 PM
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Join Date: Oct 2009
Posts: 176
Default EGR system blockage

if theres a blockagage in the EGR system somewhere it will throw a code.you might try SEAFOAM.it cleans carbon from the emission system.with the car running you pure it in the brake booster vacum hose until it dies.then let it set awhile,30 minutes or so,and start it back up.and it will smoke like crazy.then drive it like your renting it
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Old 01-07-2011, 06:24 PM
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Join Date: Jan 2011
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We have a 99 with similiar situation. Periodictly, I would have to remove the rubber air hose and spray the throttle body out with aggressive carb cleaner. I usually also took the flange that holds the throttle body butterfly off and sprayed inside the plenum of the manifold. The carbon build up would throw the code you talk about. Sometimes I would have to pull the plugs to air out the cylinders as the buildup of carb cleaner created hard starting (hydrostatic lock). There are small ports in the flanges that have to be cleared also. This solved the problem with the code. Good Luck
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