Got the dreaded spanner light on. Stays on with 2nd click of ignition and disappears when the engine starts. It has not affected the running of the car so i suspect it is some kind of stored code. I did read in the manual and a few threads on here that water may need bleeding from fuel filter. My mechanic mate tried his fault code reader (snap on one) which he says usually picks up everything but it didn't pick a thing up. Question is...will water in the diesel filter actually produce a code or does it just put the spanner light on? If it would throw up a code would it only be read with tech2?