Egr valve flow insufficient - 1999 Chevrolet Malibu

SOURCE: egr valve insufficient flow detected

You probably pulled a code p0401, insufficient egr flow. Your DPFE sensor is more than likely at fault. There has been a lot of trouble with these sensors. Then reset CEL or disconnect battery for 5 minutes.

SOURCE: exhaust recircuulation flow insufficient detected-p0401.

Can you give me a code number. Also the egr ports plug in the elbow the valve is bolted to. Remove the elbow and clean the ports.

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.
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SOURCE: Check engine light on due to issue with EGR valve

You need to reset the cars cpu,..you can do this by unhooking the negative side of the battery for about 10 minuts,then if the light comes on again,run the obd2 reader again,because there is another problem.

SOURCE: 1996 Mercury Sable with a

Before replacing anything else, it's important to clear the code before determining any more repairs are necessary. You can take the car to an autoparts store that features free diagnostic tests or you can disconnect the negative battery cable for 10 minutes to clear it. If after clearing the code P0401 still appears, then it comes down to 1 of 2 problems:

1. Replace the DPFE sensor
2. Replace the EGR valve