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Ask Ted Ritter Your Own Question
Ted Ritter
Ted Ritter, Toyota Master Tech
Category: Toyota
Satisfied Customers: 4182
Experience:  Toyota Master Tech, ASE Certified
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I need to know the drive cycle req. to ready my 01 tacoma to

Customer Question

Customer: my name is Bill and i need to know the drive cycle req. to ready my 01 tacoma to pass smog
JA: Thanks. Can you give me any more details about your issue?
Customer: originally it said bank one lean . i put both o2sensors cleaned my air flow meter and replaced a air tube going across the topfront of the motor .then the check engine light went off and i had the code cleared . but at the smog test it failed because the drive cycles werent compleated ?
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Submitted: 11 months ago.
Category: Toyota
Expert:  Dj replied 11 months ago.

Hello and thank you for trusting us with your question. I'm DJ.

Here is the drive cycle.

The procedure must be followed as exactly as possible, otherwise it will not work.

  • Ensure that the fuel tank is between 1/4 and 3/4 full.
  • Start cold (below 86°F /30°C) and warm up until engine coolant temperature is at least 160° F (typically requires at least one minute; up to 3 minutes).
  • Accelerate to 40-55 MPH at 25% throttle and maintain speed for five minutes.
  • Decelerate without using the brake (coast down) to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.
  • Restart and accelerate to 40-55 MPH at 25% throttle and maintain speed for two minutes.
  • Decelerate with using the brake [or the clutch!] by coasting down to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.

This should do it. But if you still get a code, it could be because there's a faulty component, like a downstream oxygen sensor or an evaporative system leak. Failure codes should tell you.

Please let me know if you need any additional help on this or if there is anything more I can do to help you.

DJ

Customer: replied 11 months ago.
My truck is a 5speed , so 3rd or 4th gear is okay? Then coast down meaning put it in neutral, down to 20MPH . Both times ? Thank you
Expert:  Dj replied 11 months ago.

Yes, that will work.

What code are you getting? What's not ready?

Customer: replied 11 months ago.
The Smog shop said . I need to run a drive cycle then it would pass smog if it's good on the drive cycle
Expert:  Dj replied 11 months ago.

You might want to take it to Autozone or Oreily's and get the codes scanned. They do it for no charge. At least then we would know what's hold this up.

Customer: replied 11 months ago.
It's my understanding, That everything is good ,,the computers need to run a "drive cycle" then it will pass Smog
Thank you for your help Dj
Expert:  Dj replied 11 months ago.

There are a couple of systems on the vehicle that can't be tested while the car is parked and running. There's an upstream and a downstream oxygen sensor. The upstream is before the catalytic converter. The downstream sensor is after the converter and measured the gases as they come out. This determines converter efficiency.

To do this the converter has to be hot and clean. And the only way to get it hot and clean is to drive the vehicle at at speeds with minimal throttle. Stomping the throttle and engine braking both can temporarily foul the converter and negate the test.

If the downstream sensor or the catalytic converter is faulty, it will never show ready.

That's why it's important to find out what the code is.

DJ

Customer: replied 11 months ago.
I've changed both o2sensors cleaned the Airflow meter and a air line going from the Air box to some valve on the left apron . Now my truck will pass smog test , once the computers in my truck run a "Drive Cycle" IT WILL PASS
Thank you for your help
Expert:  Ted Ritter replied 11 months ago.

Hello, I see the expert that was working with you opted out

I think what they mean is that one of the 'monitors' did not complete and pass, do you know which monitor it is, is it for the catalytic converter? It is possible for it to pass the visual test in California but not pass the monitor if the catalytic converter performance is slightly out of the allowed parameters, the computer may not run the monitor if this is the case.

The expert DJ gave you the correct procedure but it may not work sometimes, it is necessary to get the converter up to near maximum temperature to run the monitor, it's possible that the engine temperature may not come up to normal which can be caused by a bad thermostat. So make sure this is not the case.

You can also force the monitor to run, add a can of fuel treatment from the autoparts store, drive it on the highway at maximum speed limit for about 20 minutes, pull off, turn the key off and repeat then go have them check to see if it completed, you may want to consider getting a relatively inexpensive diagnostic code reader that can indicate which monitors did pass, these are about $150 and may come in handy later for diagnosing check engine lights, well worth the money, I think. It will cost you at least $100 to have the cat performance tested at the dealer.

Customer: replied 11 months ago.
I did the "drive cycle " like Dj discribed and today it passed the smog test Thanks for your help
Expert:  Ted Ritter replied 11 months ago.

Glad to do it. Best of luck to you, Merry Christmas.