If anyone can help me with this, I'd really appreciate it. I have a 99 TL with a
code P0401 that states low air flow detected in EGR valve. I replaced the EGR
and got the code back. It seemed to come back under hard acceleration, and
high revs. This seems like a vaccum leak or something. Does anyone have
any ideas on anything else I can check?
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You will have to remove the throtle assembaly and the intake chamber. you will see a small hole on the throtle body side of the intake chamber cover in carbon. Use a 8mm drill bit and clean it out. Remove the EGR valve and clean the chamber with carb cleaner.


Let me know if you need more details

 

yup also look for egr supply exaust being pluged.

or for that matter any of those passages.

also do what you can to not let that carbon get into the engine

 

Thanks, I have cleaned the ports from manifold to the egr, but have yet to
take the throttle body off and look for a clogged port there. I will when I
have some time, and let you know what I find.

 

OK, so I took off the throttle body and found the little port that has the
vaccum adjustment screw poking into it. I cleaned it out, and put the
adjustment screw back where I think I found it. I still get the same !%$#*!
engine light with same error code, P0401 low flow to the egr valve. Now
what is weird is that the TCS light comes on every time the engine light
comes back on. I can only turn off the TCS light after turning the ignition off
and then back on. The error code stays until cleared though. Two more
questions. Does this sound like an electirical/ computer problem, and how
do I test and adjust that vacuum control screw? I have a self brake bleeder
with a gague on it. Can I do it with that? Please help.

 

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It is very hard to diagnose these things from afar. Have you gone through the diagnostic table provided by Acura? If you don’t have the manuals, factory manuals, the answer is no. If you suspect an ECU problem, the best way to eliminate that possibility is with a substitute unit. I got mine from a wreaking yard, mail order. Now I have a spare; cost me 175 dollars.

It is likely that your EGR valve is sticking. How many miles do you have on the car? Where is it driven, how is it driven and how long have you had it? Japanese electronics is the best in the world, so I doubt you have an ECU issue.

What you are doing I have done on a 95 Legend. My EGR valve appeared to work just fine on the bench, yet that check engine indicator would fault from time to time. Performing the diagnostics a few more times, convinced me to accept the verdict and replace the EGR valve. Now after two years, I get no more engine faults.

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you have to remove the whole intake manifold and flip it over. look near the end where the throttle body bolts on and there will be a carbon clogged hole. cleaning it will work for a while but it will clog again. the only way to stop it is to go to the dealer and have a steel sleave installed in the hole. the problem is that the carbon attaches itself to the poreus aluminum. the carbon is a natural byproduct and cant be stopped.