The initial code indicated vapor recovery system leak. I don't recall the actual code(s) but I did the smoke test and found the purge valve to be broke in two pieces with the plastic tube connection piece broken off the solenoid. I replaced the valve nut the service light didn't go out after about a 10 days of use so I pulled her back into autozone and they connect their analyzer and got code P1490
The definition of the code is Vacuum Cut Valve (circuit)
the probable causes given are:
1) open or short circuit condition
2) Failed vacuum cut valve bypass valve
I looked up the image of the vacuum cut bypass valve and it's the round white plastic device that is interconnect to the purge valve that I just replaced. When I bought the purge valve from the Nissan Dealer Parts Dept (I couldn't find it at any auto parts store) they asked me if I wanted to replace the vacuum cut bypass valve also. I asked for a price and it was $123 so I passed. I looked it over and it seemed in fair condition. After getting the 1490 code at Autozone this morning I removed the purge valve mounting plate and took a good look at the vacuum cut valve. Seemed OK so I tried sucking on the inlet side and it held vacuum. When I energized the purge valve the vacuum into the cut valve released. That is to say that I could blow on the inlet line of the cut out valve and air flowed freely but when I sucked on it nothing. It would not allow any air to pass under vacuum until I actuated the new purge which connects to the cut out valve by two hoses. Once I energized the purge valve the vacuum I was putting on the cut out valve released. Does that sound correct? Maybe it is fixed and the service engine light needs time to reset. I removed the battery cable for a while and reconnected it but the service engine light came back on Errrrrrrrrrrrrrrrrrrrrrrr!
Wednesday, September 25th, 2013 AT 3:27 PM