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Can I save my 2000 Sentra from OBDII?

I have a 2000 Nissan Sentra, which has a history of trouble with the EVAP related codes ( e.g. P0450 ) and I can’t register the car in IL until I can get the “engine light” to go out and pass the OBDII based state inspection. About 8 years ago the light started coming on if I started it after it sat in the sun. I took it to the dealer 3 or 4 times but they could never fix it, even though the went so far as to replace the computer! I let it ride since I could pass the state inspection in the winter, when the light went out. It got progressively worse, and I barely passed two years ago when the light cleared itself and I immediately went to the state inspection station. They did a “hot start”, and the light came back on as I was leaving, and has been on since. I just paid $500 to a local mechanic who replaced the pressure sensor and the solenoid, but it comes on right away still. Any ideas?

These shops (the dealer and local mechanic) have this small advantage - they can not only inspect the car, but they also have the actual error codes. You could at least give us the codes.

Spray/clean all the electrical connectors to the EVAP valves, solenoids, sensors etc.

When I took it in, it had codes P0450, P1444, and P1446. After the repair, only the P0450 shows after the light came back on. ( I’ve been taking it to Autozone to get the codes with their policy of free readouts. )

You’re basically getting some careless service out of the folks you’ve seen. Have you taken it back to the shop that did the sensor? You should do that. Did they happen to check the wiring for the sensor? Check the vacuum lines? The P0450 is for the sensor, but that doesn’t mean the sensor is bad - the sensor is connected to things - so those things also have to be checked.

Write your State Representative and tell it you feel emissions testing accomplishes NOTHING other than providing a revenue stream for the testing authority…Whether your car passes or fails makes no difference in air quality…But if you MUST “fix it”, find a shop equipped to do a “Smoke Test” and find the leak…

Out of the 6 TSB’s related to emissions for your car 5 are evap system related with the most recent (2009) outlining specific procedures for evap diagnosis. Has this resource been used?

Google “Illinois vehicle emission testing waiver”. Possibly some help there for you.

As I mentioned, the dealer was stumped by this when the problem started years ago. They told me that they had called in the company expert, and as I said, even replaced the computer. Of course, they started with the cannister. The local guy I took it to doesn’t know anything beyond replacing things, although I suppose he did a visual inspection. He went the extra mile by replacing the solenoid for free, and indicated that that was his last trick. ( I can see it through the wheel well. It’s still shiny. ) Some of the procedures mentioned in the service manual pages I got from the “Ask a Mechanic” ad at this site are extraordinary. E.g. using nitrogen to do pressure tests and hooking up specialized equipment. It also tells you to weigh the cannister! I might try that myself if I get ambitious. I think this stuff is accessible through the wheel well.

I’m on your wavelength, except the only “revenue stream” is the state funding for the test stations. The testing is free. I think moving to OBD was seen as a cost savings. They used to do tailpipe measurements, and this involved some specialized equipment. OBD is very politically charged, though. When I had the original trouble in 2004, I found via internet browsing that it’s very much an outgrowth of environmentalism, and there were at that time enthusiastic proponents who wanted to put radio transmitters in the cars that would notify authorities if you were throwing a code.

( I just replied, but it’s not showing up. ) Answer is “no” I haven’t heard anything about these TSB’s. Are they accessible on the internet?

Thanks. That looks like a real possibility.