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how many drive cycles takes for engine light to go off after repair?

I am having new injectors put in to my 2000 Camry which we assume will solve all the misfire problems that caused the check engine light to go on. At this point since the obdii computer was zeroed, I've driven several hundred miles, so there's a good chance I've completed a drive cycle.
<br/> So is my best bet to keep driving it a few days until the engine light goes off, at which point I go in for the emissions inspection OR do I zero it and then go through the drive cycles again? Which is likely to be sooner?
<br/> Thanks....


  • edited October 2009
    just checking for any responses --have to leave soon for repair shop. Any comments?

  • edited October 2009
    not sure for Toyota, but I believe Ford is 30 minutes of normal driving 3 times (hope this helps)
  • edited October 2009
    For misfire and fuel system monitors, if the fault does not occur on three consecutive drive cycles under similar conditions, the MIL is turned off.
    Similar conditions means.
    1. Engine speed within 375 rpm compared to when the fault was detected.
    2.Engine load within 10% compared to when the fault was detected.
    3. Engine warm-up state or coolant temperature must match the temperature when the fault was detected.
    I believe you want to know how long till the light turns its self off. As you can see it is a little difficult to say exactly when your car will reset its monitor readiness status,one significant event sets you back to zero.
    I don't think it looks good for you that several HUNDRED miles of driving (I conclude with on and off engine conditions)has passed and no light self reset,it seems someting is reoccuring and preventing a light self reset.
  • edited October 2009
    Reset the CEL now and see if you guessed right and it stays off...
  • edited October 2009
    Wanted to thank y'all for your answers. turns out the tech guessed right and zeroed it, so now--with all new injectors--at least one old one was proven bad--I should only have to drive one cycle (maybe 100 miles)to get those readiness monitors to check out, instead of 3 drive cycles to reset the engine light.
  • edited October 2009
    Let us know what you mean when you say "zeroed it". Many mechanics say "cleared all codes" is this what you mean when you say zeroed it?

    How did you come to the conclusion that one drive cycle with no reoccurance of the same fault will cause the MIL to reset?
  • edited October 2009
    Yes, by zeroing it I meant cleared all the does with the computer. As for drive cycles I wrote '3' cycles to reset the engine light if it was not zeroed--based on what I heard here. and that was no guarantee either. I am hoping that with the codes cleared and the repair made, one drive cycle with no reoccurrance of the same fault will satisfy all the readiness monitors.
  • edited October 2009
    For a misfire, you may have to do some "hard" acceleration. I would have expected the light to go out with ten minutes of driving and accelerating twice. I don't feel like reading the information again right now, but if the problem is fixed, the light should have gone out by now.

    The specific misfire code may point right to the system that is causing the misfire. You might want to read your own codes with your own scan tool for around fifty dollars and get a Haynes manual to help with future codes because I expect that light to come right back on after three warmups and trips.
  • edited October 2009
    The check engine light should be turned off by whoever scans the DTC trouble code (and, records it). The car is, then, driven until the check engine light returns (or, not). The engine computer is scanned, again, and any DTC trouble codes recorded. Appropriate repairs are made, and the DTC trouble codes are erased. The car is driven, again, to see if the check engine light returns. If none does, the car is driven several "drive cycles" to allow the monitors to run their system sensor and actuator "health" checks. The monitors check just to insure that the sensors and actuators are ready to sense and to actuate.

    Toyota has a 23 page TSB (Technical Service Bulletin), dated Feb. 8, 2002, "Readiness Monitor Drive Patterns". It has lots of good stuff.
  • edited October 2009
    For around $100 you can get a code scanner that readiness monitoring. That is it will show you which systems have gone through enough drive cycles to be ready to be read. In New York State you can have one system not ready to read and still pass inspection as long as the check engine light is not on. On my car the evaporitive system is the last one to be ready,as much as 5 days driving. If you are going to buy a scanner be sure to get one with CAN ( the next standard after obdII ) on it.
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