Just bought this 08 4.7 V8 E85 dakota and it is throwing a code on the dash for gascap, I have replaced the OEM cap with one from the auto parts house. Cleared the code and low and behold the check engine light comes back on and the next day the gas cap indication comes back on. My question is WTF is going on ? Do I have to buy an OEM cap or what.

 

What was the Code? Did its description specifically say gas cap? Most "gas cap" codes are general evap leak.

 

I have read that only oem caps work.

 

I would just find a newer Dakota in a near by parking lot, pull up next to him, and you can imagine the rest ..... cheap diagnosis. You can always leave him a note if you feel bad about it, and tell him what a sexy truck he has.

 

And be careful not to break the tether!

 

It is P0440 the scan says it is a

Small EVAP leak/no flow condition

Probable cause

Defective or loose gas cap

EVAP canister or hose cracked-not connected

Purge or vent solenoid defective

Vacuum leak at the engine

Now I bought it with 63,000 miles so any of the above could be a cause, so anyone heard of which is the most common problem ?

 

Check all the vacuum linesand rubber elbows starting from the fuel tank forward.

 

I will say that if you replaced the cap with a aftermarket cap that light will not go out.These cars and trucks are so sensitive,you just about have to used the O.E.M gas cap.

 

get a factory gas cap and go from there. I tried to use locking one for mine and as soon as I installed it I got a code. Put the original one back on and the code cleared and has not come back.

 

Is your gas cap yellow?

The E85 Daks the gas cap is yellow and that's one of the things that have to be from the stealership because if not starts to throw codes....