[twicken2]

Every time I drive on a rough (dirt/rock) road, I get a malfunction indicator the next time I start the van. I still need to narrow it down to which cap it is, but its either the gas or DEF cap.. as soon as I remove and replace both and restart the van, the light is cleared.

Has anyone else had this problem?

 

[RDinNHandAZ]

Odd as I would think neither would need to be run at a vaccuum like a gas vehicle, are you saying they are? What is the code?

 

[twicken2]

I haven't pulled the code as I don't have a scan tool.. My first line of defense when I see an indicator light is to make sure all caps (including under the hood) are nice and secure.

By process of elimination I figured out its either the gas or DEF cap (most likely the gas cap I think).

I think even the diesel has a sensor on the fuel cap to prevent you from driving around leaking diesel fuel all over the road.

 

[RDinNHandAZ]

Stop into an AutoZone or other parts place and borrow their ODB2 reader. Let us know. There are many variables and though you seem to have it nailed down a reader will tell.