Emissions test; OBDII...no codes now, but are they stored? (vehicle, auto)
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2ooo GM mini van. Last year was throwing MAF and Cat converter codes and check engine light was on. Sat several months w/dead battery, now I started driving it again. Check engine light lights up w/others when turning the key (so it does work) but has not come back on in 200-300 miles over 3 weeks.
Took it to parts store and obd reader said no codes. I know they don't have the best readers. Question is---are those old codes stored, and will the emissions test pull them and fail me?
thanks for any help
edit: I never cleared anything w/the reader, codes are just no longer showing.
My check engine light was on for a few years. I had to checked out and cleared at Auto Zone and drove a few days. Light stayed off and I passed emissions. Light came on a few days later.
My question is, do they care if other lights are on? My light telling me my brakes need service came on. Will I pass? One mechanic told me it's only CE light they care about. Anyone know if that's true?
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Short answer: the old codes are stored for a time, but they shouldn't affect your emissions test if they're not active.
Long answer: IIRC, there are several things the emissions test checks for:
1) That the MIL (Malfunction Indicator Lamp, or check engine light) works.
2) That the I/M (Inspection & Maintenance) Monitors are complete. These are basically the checks that make sure the diagnostics are actually working. For example, if the misfire monitor shows ok, it doesn't mean that you don't have a misfire - it simply means that the system and circuits are working, and that the driving conditions have been met for the computer to look for misfires. If you have a misfire, there will be a misfire code stored. There are many possible I/M monitors, and most cars don't have all of them. If you've recently cleared codes and not driven enough to complete all of the I/M monitors, the emissions station can't test you. Last time I went in with one that wasn't complete, they simply said, "Your vehicle isn't ready for test," and sent me on my way with no charge.
3) Active codes. If you currently have a check engine light, it means you have a code for a problem that affects emissions. If you've fixed the problem but haven't cleared the codes with a scan tool, your check engine light will be off but the code will remain stored for a predetermined period of time until (in most cases) it will clear itself.
For example, if you had a misfire code and fixed the problem by replacing your spark plugs, your check engine light would go off when the engine stopped misfiring. The code would be stored in the computer until a predetermined number of engine warm-up cycles had been completed (40 seems to be a common number). After the 40th cycle, the computer would clear that code from history.
My question is, do they care if other lights are on? My light telling me my brakes need service came on. Will I pass? One mechanic told me it's only CE light they care about. Anyone know if that's true?
They're only concerned with emission-related problems, and those only show up at the check engine light.
My question is, do they care if other lights are on? My light telling me my brakes need service came on. Will I pass? One mechanic told me it's only CE light they care about. Anyone know if that's true?
If the battery was dead.. The codes weren't stored.. They were lost.
Where you got lucky, perhaps.. Some of the codes take a while to set. Sometimes they will show as pending, which will (generally) not light the SES/CEL/MIL.. Sometimes no code will set until the entire testing procedure has completed, which can take weeks, pending on your driving.. I know on my truck, it took 2 weeks to finish the test on the EVAP system.
Some states check whether you're in that 'diagnostic' mode, and won't pass you if you are. That's to prevent people from clearing the codes and driving right to the emissions test.
In Texas you can pass if ONE of the tests has not completed. I was able to squeak by last year with my evap system in the not ready status before it triggered any codes, but all other systems were completed and good. Finally got the canister replaced and now all system checks are completed so I can pass properly this year.
In Texas you can pass if ONE of the tests has not completed. I was able to squeak by last year with my evap system in the not ready status before it triggered any codes, but all other systems were completed and good. Finally got the canister replaced and now all system checks are completed so I can pass properly this year.
MA is the same way. You can pass with one incomplete monitor.
Whenever I had a car with a minor CEL issue (i.e. a non-critical issue like an EVAP leak) and needed a sticker, i'd reset the codes with my scanner and wait until there was just one incomplete monitor left and head right in to get my sticker. I'd get it and be on my way. Several hours later, the check engine light came back on.
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