99 Lumina with 3.1, P0401 trouble code - Chevrolet Forum - Chevy Enthusiasts Forums

Go Back   > >
Log In 

Monte Carlo & Lumina Since the 1970s, the Monte Carlo has been an icon of American stock car racing. A 4-door version, the Lumina, was produced in the late 90's.
Platform: A-, G-, & W-body

LinkBack Thread Tools Search this Thread
Old 07-05-2011, 02:00 PM
CF Beginner
Thread Starter
Join Date: Jul 2011
Location: MD
Posts: 1
Default 99 Lumina with 3.1, P0401 trouble code

I can't seem to get ride of the P0401 EGR insufficient flow trouble code. I first replaced the EGR valve with an AutoZone "Duralast" valve. I checked the intake manifold passage and exhaust pipe passage, both were clear. The "service enginesoon" light went out for about 4-5 weeks. I thought I had fixed it. Soon there after the light came back with the same code (P0401). Some research I found indicated that a bad MAP sensor could cause this. It was cheap, so I replaced it. No help. Now thinking the AutoZone (Chinese made) valve may not meet GM standards, I purchased an OEM Delco EGR valve. This time I blew air intake cleaner into the manifold passage, removed the air snorkle and blew compressed air into the passage....all clear. I could see and hear the compressed air going into the manifold. Next I blew compressed air down the exhaust pipe and it was clear. Next I started the engine with the EGR removed. The vacuum side would nearly suck your finger into the manifold. The exhaust side would blow your finger off....ALL PASSAGES ARE CLEAR. I put the OEM valve in place and cleared the code. Everything was fine AGAIN for about 6-8 weeks. Now the code is back and I have no idea what to do. Please send any ideas you may have. I have heard that a bad PCM can do this. The car has 172,000 miles and runs great. No performance issues.

Last edited by National1; 07-06-2011 at 06:18 AM. Reason: misspelling of a word
Reply With Quote
Old 08-05-2011, 06:36 AM
CF Beginner
Join Date: Aug 2011
Posts: 3

I had that same exact problem with my 98 Lumina. I had no performance issues, and the passages all seemed to be clear. I still blew cleaner down them for good measure, but it wasn't until I removed the air intake assembly and visually saw the junction between the hot exhaust gas and the intake air that I found a most impressive partial obstruction that still hadn't come out in spite of my efforts. A little well targeted carb cleaner and a screwdriver fixed it after that.
Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Service Engine Light.... P0401, P0121, P1345 Ryanater Silverado & Fullsize Pick-ups 1 08-14-2012 01:16 AM
98 Malibu EGR low flow (code P0401) mpeel Malibu 6 08-05-2011 11:16 AM
im back with more trouble with my k 10 carb trouble..... dozer157 Silverado & Fullsize Pick-ups 4 09-08-2009 07:32 PM
1999 chevy lumina error P0401 terry Beretta, Corsica, & pre-1995 Lumina 0 10-12-2008 07:07 PM
98 Malibu EGR valve code P0401 mpeel Malibu 0 02-05-2008 03:37 PM

1999, 99, carlo, chevrolet, chevy, code, egr, gm, lumina, monte, obd, p0401, po401, trouble, w

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -5. The time now is 06:42 AM.