1999 Chevy Blazer with code P0402
#1
07-27-2010, 07:23 AM
1999 Chevy Blazer with code P0402
This morning as I was driving to work my "check engine soon" light came on. When I verified the OBDII code reader code, it stated a code P0402 1/2. Can anyone give me some insight on this code? 
#2
07-27-2010, 05:40 PM
P0402 - Exhaust Gas Recirculation Flow Excessive Detected
Basically the exact opposite of:
P0401 - Exhaust Gas Recirculation Flow Insufficient Detected
The diagnostic steps will be somewhat similar. This is typically caused by an EGR valve that is stuck open by a chunk of carbon. Remove the EGR valve and clean it. When you reinstall it, do so with a new gasket. There is an aftermarket gasket that has an integrated screen that decreases the possibility of this happening again.
Basically the exact opposite of:
P0401 - Exhaust Gas Recirculation Flow Insufficient Detected
The diagnostic steps will be somewhat similar. This is typically caused by an EGR valve that is stuck open by a chunk of carbon. Remove the EGR valve and clean it. When you reinstall it, do so with a new gasket. There is an aftermarket gasket that has an integrated screen that decreases the possibility of this happening again.
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