Went from P0401 to P0402 OBD code

[njlarry]

After replacing the DFPS on my 2002 6 cyl Explorer the check engine light (P0401-restricted ERG flow) stayed off for several thoushand miles but just came back on with P0402-excesive ERG flow.
Does this mean the ERG valve must be replaced? I'm sorry I got the new DFPS valve from AdvanceAuto and it fit like crap. It will not allow the connectoer to click lock on and and I wonder if a lose connection would allow an excessive EGR flow.

 

[dolluper]

Re: Went from P0401 to P0402 OBD code

Good place to start is the connector.....try the old connector a little snipping and soldering.....check for carbon build up in EGR

 

[KewlBird]

Re: Went from P0401 to P0402 OBD code

I can't remember if the EGR on those 4.0liters is vacuum fed but if it is (I checked and it is vacuum), pull the vacuum line off of the EGR and see if the idle changes. If the idle changes, your problem is elsewhere. If it doesn't change, apply some vacuum to the EGR, if you don't have a vacuum pump you can use a piece of hose and suck the air out. You should see the idle change, and motor will probably cut out. If there is no change, your EGR is bad.

 

[njlarry]

Re: Went from P0401 to P0402 OBD code

Thanks KlewBird!
Disconnecting the vacuum line did not change the idle but applying a vacuum caused the engine to stall. So if the DFPE and the ERG are ok what should I look at next?

 

[180shabah]

Re: Went from P0401 to P0402 OBD code

what should I look at next?

A new boat, just make sure it is big enough for live-aboard, then you won't need the truck.