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Doug
Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 8570
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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2001 Mitsubishi montero: The check engine light is on

Customer Question

Hello. I have a 2001 Mitsubishi montero with 155K on it. The check engine light is on. I took it to my mechanic and after he scan it, he told me that I needed a Mass air flow sensor. So I replace it. The check engine light went off,but now I have to dive it like 100 miles to "reset the computer" before I go get the yearly inspection. My question is, if I drive 100 miles will it reset the computer or not ? and if not what can I do to reset it ?
Submitted: 6 years ago.
Category: Mitsubishi
Expert:  Doug replied 6 years ago.
Hi,
They are referring to the OBD drive cycle monitors that are required to be "complete" for your inspection. When you have your inspection done, if you are in a state/county that does monitor status tests, they will hook up to your computer and verify that all tests are complete and passed. If any are listed as not complete (or obviously 'fail'), then you will not pass your inspection.

100 miles is just a ballpark rule of thumb to assume that all of your monitors have had time to complete. Realistically with normal driving they will all complete within a few days or less; they are run constantly whenever the testing criteria is met.

If you wanted to force the monitors to run, you can do this, it is quite a drawn out affair however, which is why it is common to just say "drive the vehicle", as they will all run relatively soon.

For reference, the forced patterns are similar to this:
Drive vehicle to 38mph and hold for 90 seconds, decelerate to 18mph, accelerate to 38mph and hold for 20 seconds. Decelerate to 18mph, hold, then decelerate to a stop.
Repeat 3 times.

Et cetera. That is one of the force patterns; there are 18 for this car, and they all must be performed with a scan tool connected to verify correct output.

For simplicity, it is much easier to just drive the car. If you would like, I do have a listing of all applicable drive patterns for your vehicle if you are in a rush to get inspected. Just let me know if you would like to check them out and I can upload them.

Thanks
Customer: replied 6 years ago.
Ok please upload the drive patterns. I'm try them. After the airflow sensor was change,I get the code on the scanner "O2 bank..........." That is why my mechanic say I should diveit to reset the computer.
Expert:  Doug replied 6 years ago.
No problem, give me just a few minutes as there are several.

Regarding a code reoccurring, this is happening because there is still a problem. Drive cycles and force readiness tests only confirm that everything is OK, they will not correct and existing issue.
Expert:  Doug replied 6 years ago.
List of applicable monitors:

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Actual force pattern drive cycles for the patterns listed in the right column:
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Sorry for the delay, as you can see there were quite a few to capture.

Again, if you have a trouble code that is recurring, these will NOT correct any issue, they will only force the computer to run it's diagnostics early. If you have a trouble code that is still being set, it will need to be corrected first. If you have the code # XXXXX'd be happy to help you with that as well, just let me know.