I have read previous postings on this subject but can't find the definative answer.
02 Jetta w. 1.8t
Code 18613 Cooling system performance issues
Car runs fine. Engine runs at 190 w/ no problems!! Spoke with garage and they called round.. sounds like a shotgun appraoch. Thermastat, Engine cooling sensor, possibly even a change of wiring harness. HELP!!
If you have had this problem or know of a solution..please help!