2002 Red Blazer 4x4....light came on intermittently for a month, I needed some exhaust work..OK. good to go for about 3 months,..light came on, stayed on...cleaned the MAF....good to go for a month..light came on..code P0400..Generic Evap emissions systems.... [O2 sensor??]....re-set code.
The light is out now for a week or so........runs good, good mileage [for the Blazer]
Any clues? advice?
I'm 70, so can't do some of the type work I used to do.
Thanks for any help
Bluesky

 

My references do not list anything for P0400 in your application... Are you sure this was the exact code?

The generic OBD2 title for P0400 is 'Exhaust Gas Recirculation (EGR) Flow'. 2002 was the transition year for the EGR valve. I'm not sure what they did with it, but it used to be located on the lower intake manifold in front of where the upper radiator hose connects, between the alternator & the a/c compressor. If you have the older style, you could try cleaning the EGR valve and installing a screened gasket. There is an article in the Tech Article (DIY) section on how to do this.

Also, what were the specific codes that you received previously?

 

Don't remember the other codes, [senior moments] but the cat was trashed and stuffing up the exhaust and caused a leak in the exhaust at the manifold.