[QUOTE=Philster]
My daily commuter, a 1997 VW Jetta, is hovering around 115,000 miles and the check engine light has been on. It is overdue for an emissions inspection in NJ, and a check engine light means ‘‘don’t even bother bringing it in’’, as they do not inspect cars with the engine light on.
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I can shed some light on this one, having encountered a similar situation in TN.
First of all Emissions inspections rely heavily on your car computer’s output to determine what issues exist. The engine light is directly triggered by your car’s self diagnostics. According to my testing center and confirmed by my mechanic, once certain errors have been flagged, some diagnostics may no longer run until the computer has been reset. Therefore a car with the engine light on may mean that further problems go undetected. For the testing center, this means that a conclusive result is not possible while the engine light is on.
Regarding the disabling of the light itself, this is irrelevant. One of the first things the testing center does is hook into your car’s computer to read the diagnostic status. This will immediately detect any conditions that would have caused your engine light to come on and is an automatic failure.
Regarding resetting the computer, I have been told by my testing center here and one mechanic that after your car’s computer diagnostics is reset, it can take several hundred miles and several days or more to rerun the car’s diagnostics. This is even in my car user’s manuals for my Nissan and Chevrolet. After the computer has been reset, the car must run (and complete) all it’s diagnostics. During this time the computer reports that it has not completed it’s diagnostics and the testing center will detect this immediately and is an automatic failure since “no result” is inconclusive.
HOWEVER, as I was told by my favorite mechanic, the recommendation of hundreds of miles and days of elapsed time is rarely accurate. In my own personal experience on 2 cars of different manufacturers, it took me only two 15 min work commutes to complete said diagnostics. (Note that there is no notification for the driver when the diagnostics complete. The only way to know if it is done is to read the codes off the computer) Basically my mechanic said you just need to do some “around town” driving and some “highway” driving in order for the diagnostics to run. He also said that just because your engine light triggered once does not necessarily mean it will trigger again or trigger immediately. In my case, my Nissan had a bad flow sensor. He reset the computer and I drove it to work twice and then had it tested. It passed. One week later my engine light was back on but I had bought myself a year’s reprieve.
A number of the items tested cannot be easily or adequately duplicated and tested in the shop. Evaporative faults and Oxides of nitrogen (nox)
[QUOTE=dalej42]
Of course, car dealers are the number one advocates of mandatory tests. Gets people into the repair shops and also may encourage them to just buy another car than go through inspection again with a car which has turned into a money pit.
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Speaking as a former car dealer technician and car company technical employee, you are about 180 degrees off here. Car dealers and car companies as a group hate ever changing regulations, and systems that getting ever more complex.
[QUOTE=Gary T]
Which may well be true, but is rather unhelpful in that it’s not up to him. It’s up to the state of New Jersey, who insist you bother with the repair (or up to you if you decide to sell the car).
Well, maybe. Let me clarify: RESETTING THE LIGHT (clearing codes) IS NOT ENOUGH. The computer’s memory has to be totally cleared - not just of the code that activates the light, but of the adaptive strategy that reacts to the condition that set the code. It’s a more involved process than on many other cars. Typically it involves disconnecting both battery cables from the battery and touching the cables to each other for a few minutes, and/or disconnecting the complete wire connector to the computer for at least 15 minutes. Then the idle adaptation has to be reset to a base setting.
I’m suspicious that the shop does not know about this and did NOT do a PROPER AND COMPLETE reset. If this is the case, it’s still possible that your problem can be solved without replacing the throttle body. And if they don’t do the right reset, I would expect the code (and light) to return even with a new throttle body. I wonder if this has happened to them and that’s why they’re doubtful that a replacement would fix the problem.
My suggestion: satisfy yourself that they DEFINITELY KNOW (not think they know) how to work on this system, or take the car to a shop that does.
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I will absolutely ensure that this was done prior to any decision.
[QUOTE=minor7flat5]
Don’t do that before you let me take a few pieces off it for my '98 Jetta
I’m just up the road from you and you will have the satisfaction of helping a fellow doper out.
Have any of your windows fallen down into the doors yet?
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My Jetta is interesting. It has power everything, tilt wheel, cruise control A/C, sun/moonroof but has hand crank windows. Never had a problem with them. On my Dodge truck, the drivers power-operated window fell down into the door twice.
I got the Jetta in 1997 it when it was a few months old/used. I was told that a women ordered it that way (crank windows) because her dog was always lowering the windows on her other car via the power window button, so she ordered everything and deleted the power windows.
