Not P0442
PounDDer said:
I had the same problem on a cavalier once. It was a bad fuel cap. You can try that first.
No No No
... you are thinking of P0442 which is caused when the Evaperative Emmissions (EVAP) test fails on a gasoline-powerd vehicle. The EVAP test uses an air pump to build-up a small pressure in the airspace above the gasoline in the tank. Then, it is sealed off and a timer-sequence is initiated to determine how long this pressure is maintained.
A P0442 is flagged when the pressure cannot be built up at all. (A loose gascap is the most common cause of P0442)
A P0455 is flagged if the second part of the test fails (cannot maintiain the pressure.)
In fact, there are an array of P044x codes which are all related to the EVAP system.
Fixing cars is a peice of cake when one understands and KNOWS how the systems work.
Why do gasoline vehicles have an EVAP system?
1) To reduce gasolene fumes from getting into the atmosphere
2) To prevent EXPLOSIONS in underground parking decks. (Imagane if all the cars in an underground parking deck were leaking gasoline fumes into the air.... any spark would cause an explosion)
BTW: I do not beleive that TDI even *HAS* an EVAP system... so all of the above is just for folks who wish to have their knowledge enrichend.