po400 egr flow how do I fix it?

[mrdave]

I have a 96 nissan pickup. check engine code is po400. If I replace the egr valve ($150!) will this fix the problem or should I check something else first? The problem occured after I replaced the battery.

[MaximA32]

Is there a rough idle at the first start up of the day? If so, I'd say yes, replace the EGR valve. If there isn't, switch the two vaccum hoses that run into the EGR around and see if it changes anything. If it runs worse, switch them back around and replace the EGR.

[mrdave]

It runs perfect,at idle and full load. No change in performance. It is odd that it happened after I changed the battery. I was out of town for 1 day when my battery failed. My wife had the neighbor put in an extra one I had in the garage. Maybe they shorted something?? That is why I am asking if there could be something else in the system electrically before I dish out $150 for a new EGR. I would like to reset the code to see if it will come in again. How do I do that?

[MaximA32]

Autozone should do it for free.