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Posted (edited)

In Arizona- just got her about two weeks ago, have put 1,000 miles on it both highway and city driving between phoenix and California along driving it back to phoenix form Las Vegas when I got it.

 

Anyway, I failed smog because the catalyst was “not ready” 

 

anyone else have this issue? 
 

edit- 2021 Yukon denali 6.2 l87 10speed 

Edited by Denali_2021
Vehicle details
Posted

Different monitors do their test only under conditions specific to that monitor.  you MIGHT find the drive cycle conditions for the monitor that isn't ready on this site: https://lemon-manuals.la/

 

If it's not there, then it should be on alldata.com for your truck, but it requires a paid subscription.

 

And you need to know which specific monitor isn't ready.

Posted (edited)

I had a similar problem years ago and it ended up being the positive battery cable that ran to the main fuse block/ECU. It looked fine but when I sliced it open it was badly corroded. 

Edited by mysery1
Posted
15 hours ago, Denali_2021 said:

In Arizona- just got her about two weeks ago, have put 1,000 miles on it both highway and city driving between phoenix and California along driving it back to phoenix form Las Vegas when I got it.

 

Anyway, I failed smog because the catalyst was “not ready” 

 

anyone else have this issue? 
 

edit- 2021 Yukon denali 6.2 l87 10speed 

 

 

Do you have any DFM defeat devices like the Range modules?  

Posted

Also here's the drive cycle for a 2021 Yukon with V8.  DO NOT USE THE CRUISE CONTROL WHEN RUNNING DRIVE CYCLE!!!!!:

 

Warning: Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.

Note:

  • You have completed this procedure when all parameters display Complete.
  • Short stops for traffic will not affect the procedure.

Note: Do NOT use cruise control during this procedure.

  1. Ignition/Vehicle » Off — For greater than 8 h
  2. Verify the scan tool parameter: Cold Start-Up = Yes
    • If not the specified state

      Ignition/Vehicle » Off — For greater than 8 h & Repeat this step

    • If the specified state
  3. Ignition » On / Vehicle » In Service Mode — For 1 min
  4. Engine » Idling — For 2 min
  5. Drive the vehicle while maintaining the following conditions for 20 min:
    • Part Throttle
    • Vehicle Speed = 24 to 97 km/h (15 to 60 MPH)
  6. Safely stop the vehicle
  7. Operate the engine/vehicle within the following conditions:
    1. Accelerate the vehicle to 64 km/h (40 MPH)
    2. Accelerate the vehicle from 64 to 97 km/h (40 to 60 MPH) @ Throttle position between 10% and 13%
    3. Release the accelerator pedal and let the vehicle coast down with the brake pedal released — For greater than 20 s
    4. Accelerate the vehicle from 64 to 97 km/h (40 to 60 MPH) @ Throttle position between 13% and 16%
    5. Release the accelerator pedal and let the vehicle coast down with the brake pedal released — For greater than 20 s
    6. Accelerate the vehicle from 64 to 97 km/h (40 to 60 MPH) @ Throttle position between 16% and 19%
    7. Release the accelerator pedal and let the vehicle coast down with the brake pedal released — For greater than 20 s
    8. Accelerate the vehicle from 64 to 97 km/h (40 to 60 MPH) @ Throttle position between 19% and 22%
    9. Release the accelerator pedal and let the vehicle coast down with the brake pedal released — For greater than 20 s
    10. Accelerate the vehicle from 64 to 97 km/h (40 to 60 MPH) @ Throttle position between 22% and 25%
    11. Release the accelerator pedal and let the vehicle coast down with the brake pedal released — For greater than 20 s
  8. Maintain steady state throttle at 89 km/h (55 MPH) — For 10 min
  9. Safely stop the vehicle

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