My 2004 discovery (62k) is having a re-occuring service engine soon light (solid, not blinking), the orginal fault code was for a LARGE EVAP LEAK, the deler told me that they used the T4 scan tool and verified a DTC#-P0455 Large Leak Detected-----the dealership tech tested the system and couldn't find any problem or leak, the system was reset, the vechile pased a road test,......fast forward 2 weeks and the service engine light is back.

the vechile is preforming fine and i am trying to avoid going back to the delareship without some more insight into this issue.....the dealership charges $120 just for an oil change

they talked about doing a smoke test if the fault occured again (sounds expensive)

Any thoughts on what this could be ?

thanks

 

Start by replacing your gas cap, if that does not do it then you may need the smoke test which may or may not find the problem.
A bad or loose gas cap can set off this code.

 

thanks.........this sounds like a good place to start

GEOFF

 

Just to add up, you should also check your overall engine performance. You should check every part of the engine especially the Rocker Arm Stud Girdle because it helps your engine power to have a good performance.

 

This statement caught me off guard. Yes it is always good to check your system over, but nothing you mentioned has nothing to do with a Gross EVAP leak and a EVAP will in no way effect your engines performance, it only allows gas vapor to escape into the air.