P0401?
 

So i have the SES light on and I read the code p0401. i know the code is for the egr flow but how do i fix it? I cleaned the egr with sea foam deep creap and put it back on. It came on after 20 min on the freeway. Also is there an upgrade for this code for the 95 blazers ecu? I have also looked around for information to this code but no help yet.

RE: P0401?
 

Did you also clean out the egr passage?? If not you should try cleaning this to. If this doesn't work then you need to get your DPF (differential pressure) sensor checked out. If its not that then you might just have a faulty egr valve.

RE: P0401?
 

i cleaned the passage by spraying the sea foam down it and running it for a few seconds to blow the carbon out. how do you check the DPF?

RE: P0401?
 

sorry but i'm not exactly sure how to do that. you have to check the voltage it is putting out. I'm not sure exactly what the voltage for it should be. maybe swartlkk or someone like that would know. If not I would just take it to a shop and tell them to check it out.