Check Engine Light - 97 Aerostar

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Yes, but he could also twist the cap a few more clicks because the Check Engine light is on and think that he cured the problem. Maybe he read somewhere that the Check Engine light usually comes on because the gas cap is not seated properly, which is true but ignores the hundreds of other reasons that the Check Engine light might come on.
He could scan for codes, but he refuses to acquire a scan tool. If he had the scan tool, he could reset the computer and turn the Check Engine light off, and all of this discussion would never happen.
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On Sat, 8 Mar 2014 08:27:38 -0800, "Jeff Strickland"

the problem - - -
Last time I had an evap related check engine light it was because SWMBO left the cap off when she filled up with fuel.
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snipped-for-privacy@snyder.on.ca wrote:

it wouldn't apply to an ancient beast like a 97 A-Star but on modern vehicles the PCM will run a quick-test on the EVAP after each "refueling event". That's how the those new gas cap lights get triggered vs. the regular CEL.
the more ya know!
GW
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wrote:

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snipped-for-privacy@snyder.on.ca wrote:

wanna see it.
GW
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if you drive with the gas cap loose, missing, ar faulty. Just like EVERY OTHER OBD2 equipped vehicle.
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snipped-for-privacy@snyder.on.ca wrote:

yeah, no shit, and they DO NOT have the Check Gas Cap light like newer vehicles. (like I already said)
GW
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On Fri, 7 Mar 2014 00:39:31 -0800, "Guv Bob"

It is part of the OBD2 spec - and it is a requirement in order to make SURE that nobody can "cheat the system" The computer in the car is doing a very complex check on several hundred different parameters, and validating the response to be sure all the sensors are there, reporting, and accurate. The fact that the evap monitor WILL reset itself after you put the gas cap on is really a concession to the owner - he does not need to pay a dealer or garage to reset the computer - yet it maintains the integrity of the epaporative emission control check for the EPA.
Now, since MOST jurisdictions allow ONE monitor to fail and still pass the smog test, you COULD reset the codes and get all the monitors except the evap set (can be done in less than 15 miles) andSTILL pass with a faulty evap system - but with your luck it would reset as you pull in for your test, and the light would come on - and you would fail. (assuming you had an unresolved evap problem)
Used to be they did a cap check as part of the test - but not any more.
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You are entirely right, except that they allow one or two monitors to not be complete and still let the test proceed. You said they allow one to fail, but they really allow one to be incomplete -- still running.
There is a subtle difference in a monitor that has failed, as you said, and is not complete yet. If the monitor has indeed failed, then it is compete and did not pass the self-tests that you described. If the self tests have not finished running, that is the condition for which the vehicle can still be submitted for testing.
I'm not sure about the allowance of one or two monitors still running. When I had this issue, they let me test with two still running, but I get a mixed explanation as to whether they still allow two or only one, or if they allow two for cars that are older and one for cars that are not so old. But, you are also correct here, most (if not all) jurisdictions that test for smog do not require that all monitors be finished running the tests.
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On Fri, 7 Mar 2014 14:18:20 -0800, "Jeff Strickland"

Some places allow one monitor to fail to complete, some two.
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wrote:

I know I can reset it with a code reader. Was hoping there was a way to do it with a jumper instead of disconnecting the battery.
+++JStrickland++++++++++++++ No, there is not. Whether you do a hard reset with a scan tool, disconnect the battery (which the specification says is not supposed to reset) or simply drive the vehicle until the computer recognizes that the condition has been cured, it still takes the same number of drive cycles to set the readiness monitors to ready, or complete (which is the proper term).
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or using the diagnostic tool?
After driving for a couple of weeks, the light went out. Then a few days later came back on. Then a couple days later went off again. I will venture down to the auto parts place today and get the code. Yes, I don't like rushing into anything. LOL!!
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