I just got a 2000 Land Rover Discovery Series 2 (less than 84,000 miles) on Saturday. Service engine soon light came up got the code P0040? What all do i need to check? I took it to the dealership about it since i have a 30 day warranty. They checked, gave me the code, and said something was lose. They tightened everything up and i believe cleared the light. But if it comes up again i should take it back. Just want some insight..Please. Thanks.

 

Part of emission system, be sure they fix it or you won't pass inspection. Here's page from the shop manual.