Code 71-EGR system malfunction
Thread Starter
Driver School Candidate
Joined: Apr 2005
Posts: 15
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From: CA
Code 71-EGR system malfunction
I am having a problem with my '95 SC 300 and a pesky check engine light. It is coming up with a code 71 (EGR system malfunction). I have replaced the EGR valve and modulator. The light comes back on after about 50 miles of driving. I'm getting tired of the "guess and check" method. Could the EGR temperature sensor be the culprit? Any help is appreciated.
I just had my egr valve and egr modulator replaced recently and just replaced my egr temp sensor as well yesterday...after about 50 miles of driving, I'll get that pesky check engine light as well (Which is also a code 71).
The valve and modulator tested out fine and the replacement temp sensor looked like it was in decent condition...all that's left is for me to try GS4_Fiend's testing methods,clean the clogged pipes and maybe replace the egr solenoid.
The valve and modulator tested out fine and the replacement temp sensor looked like it was in decent condition...all that's left is for me to try GS4_Fiend's testing methods,clean the clogged pipes and maybe replace the egr solenoid.
yeah i dealt with this issue forever, replaced egr valve twice replaced vacuum modulator twice. removed intake manifold cleaned all egr passages. Eventually i just removed the system and blocked off the passages + rerouted vacuum. Just gotta throw a resistor in whenever the check engine light actually starts bothering me
The EGR passages almost never gets clogged on the exhaust side(from EGR down to exhaust manifold). It get clogged on the intake side because temp difference from hot to cold. To determine if ur EGR passages are clogged on the intake side, apply vacuum to the EGR. D
I just had my egr valve and egr modulator replaced recently and just replaced my egr temp sensor as well yesterday...after about 50 miles of driving, I'll get that pesky check engine light as well (Which is also a code 71).
The valve and modulator tested out fine and the replacement temp sensor looked like it was in decent condition...all that's left is for me to try GS4_Fiend's testing methods,clean the clogged pipes and maybe replace the egr solenoid.
The valve and modulator tested out fine and the replacement temp sensor looked like it was in decent condition...all that's left is for me to try GS4_Fiend's testing methods,clean the clogged pipes and maybe replace the egr solenoid.
The EGR passages almost never gets clogged on the exhaust side(from EGR down to exhaust manifold). It get clogged on the intake side because temp difference from hot to cold. To determine if ur EGR passages are clogged on the intake side, apply vacuum to the EGR and see if it stumbles alot, a little or nothing. If it doesnt stumble at all most likely you got clogged up EGR passages or a stuck closed EGR valve.
I just had my egr valve and egr modulator replaced recently and just replaced my egr temp sensor as well yesterday...after about 50 miles of driving, I'll get that pesky check engine light as well (Which is also a code 71).
The valve and modulator tested out fine and the replacement temp sensor looked like it was in decent condition...all that's left is for me to try GS4_Fiend's testing methods,clean the clogged pipes and maybe replace the egr solenoid.
The valve and modulator tested out fine and the replacement temp sensor looked like it was in decent condition...all that's left is for me to try GS4_Fiend's testing methods,clean the clogged pipes and maybe replace the egr solenoid.
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Thread Starter
Driver School Candidate
Joined: Apr 2005
Posts: 15
Likes: 0
From: CA
I believe my problem was the EGR temp sensor. I removed it and noticed it has some oxidation on the business end. After wire brushing the stuff off and doing a resistance check, it seems to be functioning properly. It has been 3 days and no check engine light.
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I'm almost at a total loss here, My mechanic couldn't find anything that was clogged in the EGR system, The egr valve and egr modulator are both new units (Both were tested prior to being put on) My old torn egr temp sensor was replaced with a decent used one from a junkyard...All that's left is the egr solenoid which wasn't replaced at all, I'm taking my car in Monday to a guy who specialzes in smog repairs...This sucks!
Btw, How do you check resistance on the egr temp sensor?
Btw, How do you check resistance on the egr temp sensor?
Why dont you just change the vsv yourself? Its not hard.
I'm almost at a total loss here, My mechanic couldn't find anything that was clogged in the EGR system, The egr valve and egr modulator are both new units (Both were tested prior to being put on) My old torn egr temp sensor was replaced with a decent used one from a junkyard...All that's left is the egr solenoid which wasn't replaced at all, I'm taking my car in Monday to a guy who specialzes in smog repairs...This sucks!
Btw, How do you check resistance on the egr temp sensor?
Btw, How do you check resistance on the egr temp sensor?
Thread Starter
Driver School Candidate
Joined: Apr 2005
Posts: 15
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From: CA
By business end, I mean the end that is screwed into the EGR valve. To check resistance, dip the tip into cooking oil and heat it up. The resistance should be between 69-89 Kohms at 122 degrees F, 12 to 15 kohms at 212 degrees F and 2 to 4 kohms at 302 degrees F.
Thread Starter
Driver School Candidate
Joined: Apr 2005
Posts: 15
Likes: 0
From: CA
