Question about 2004 Chevrolet Blazer
Remove egr valve and clean the hole and egr itself
hope it helps
Posted on Oct 18, 2013
The egr may be a misread,,change the air flow filter and see if that helps ..it does not take much to make any engine light to stay on ..I feel it is a misread
Posted on Oct 17, 2013
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
New users get to try the service completely Free afterwhich it costs $6 per call and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
SOURCE: Insufficient EGR Flow problem
Specifically DTC P0401 is "Exhaust Gas Recirculation (EGR) Insufficient Flow". Now this is where we have to be careful when we read a code. In this case it is not saying the EGR valve is bad, it's saying the EGR flow is too low. Now it could be because the EGR valve is bad. Or it could be a clogged EGR tube or a broken vacuum line. This is why you have to be careful and check the whole system before you go changing parts.
The PCM tests the EGR system during deceleration by momentarily commanding the EGR valve to open while monitoring the Manifold Absolute Pressure (MAP) sensor signal. When the EGR valve is opened, the PCM should see a proportional increase in MAP. If the expected increase in MAP is not seen, the PCM notes the amount of error that was detected and adjusts an internal fail counter towards a fail threshold level. When the fail counter exceeds the fail threshold level, the PCM will set DTC P0401. The number of test samples required to accomplish this may vary according to the amount of detected flow error.
Normally, the PCM will only allow one EGR flow test sample to be taken during an ignition cycle. To aid in verifying a repair, the PCM allows twelve test samples during the first ignition cycle following a scan tool Clear Info or a battery disconnect. Between nine and twelve samples should be sufficient for the PCM to determine adequate EGR flow and pass the EGR test.
To check the system first you need to remove the EGR valve and if it is clogged or broken. If it is, clean or replace it. If it is okay, then remove the EGR inlet tube from the exhaust manifold and the EGR outlet tube from the intake manifold. If either or both are clogged, clean them out or replace them. Then check the ports in the manifolds themselves to see if they are clogged. If so, clean them out.
When you are done, disconnect the battery for about 30 seconds to clear the code and drive the car to see if the light comes back.
This should take care of the problem. If not, then you will need to put a scan tool on the car and see what the EGR control system is doing wrong and correct it.
The Valve on this car is electronic, so, unfortunately a vacuum pump will not work for testing.
If you have a scan tool, you can command the pcm to open the valve to see if the valve itself is working.There are really only4 things to go wrong with these things, PCM, wiring,the valve itself, or plugged passages. I have never seen the pcm cause this problem, or the wiring for that matter. If you say you have pulled the EGR and checked the intake passages, then I would be pretty confident in saying the the egr valve itself is bad.
Thanks for using FixYa - a FixYa rating is appreciated for answering your FREE question.
Posted on Mar 18, 2009
check tps sensor (throttle position sensor in backside of the throttle cable) and map sensor (manifold absolute pressure on front little 1 inch sensor with vacuum line) make sure there plugged in. the ecm (engine control module driver side inner fender) and tcm (transmission control module under dash) both need the data to know when to upshift and increase fuel/air. Otherwise the computer runs default values and guesses off of other sensors giving poor performance. also disconnect battery for 15 min. usually resets aveo service lights if you dont have a scanner.
Posted on Aug 02, 2009
SOURCE: bad egr valve
You can try cleaning it. Go to your local parts store and buy a can of brake cleaner. Remove the EGR valve and spray it into the valve and let it set 8 hours. Pour out the cleaner and clean the carbon off with a wire brush. Reinstall the valve and see if that helps. If not, you will have to buy a new one and it will not cost $316 if you DIY.
Posted on Oct 18, 2009
Tips for a great answer:
Sep 15, 2014 | Cars & Trucks
Feb 11, 2014 | 2009 Mini Cooper S
Oct 17, 2013 | 2006 Chevrolet Malibu
Sep 10, 2011 | 2002 Saturn Sl
May 04, 2011 | Ford Escape Cars & Trucks
Mar 22, 2011 | 2001 Chevrolet Malibu
Jul 02, 2010 | 2006 Dodge Caravan
Oct 21, 2009 | 1999 Chevrolet Malibu
Sep 18, 2009 | 2005 Chrysler PT Cruiser
62 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: