This has to do with my wife's 2003 VW diesel Jetta, but information on this topic maybe useful for any car. I'd thought I'd ask here before I call Click 'n Clack.
The check enginel light went on about a month ago. The dealer said the thermostat was bad (from a code?), so it was replaced, and we had the coolant flushed and replaced. Now the check engine light is on again, but this time I took it to my mechanic (for my daily driver, not Boxster). He said he got "codes" for the thermstat and for the coolant temperature sensor. I had him change the temperature sensor and he reset the codes. The light is on again. So, I called the dealer and he said that if I bring the car in the code would indicate that something is wrong with the cooling system, but what is wrong would need more study. It could be the thermostat, it would be some air got into the system when it was flushed, it could be the temp senor, it could a malfuncition water pump.
So, here is the essence of my question -- I thought, maybe wrongly, that the "codes" indicate something specific. Like a thermostat, a temp senor, a water pump. I guess I thought that the level of diagnostic precision was to tell you/the mechanic precisely what needs to be fixed or replaced.
I am not a dyi guy (other than emaculate detailing), so I don't have a diagnostic kit for my Boxster or any other car. But, I'd like to know how best to handle mechanics when they talk about "codes" for any car. What do they really tell you? Something specific or a general area to look at? Or some in between level of information?
Thanks, Bob
1999 Arctic Sivler/black/black (sold)
2008s Silver/black/black - so predictable
2011 Outback
8/24/2011 first Grandson