O2 sensor and smog check readiness

[+ManifoldPSI]

Trying to get my '25 5VBW smog ready. Smog check failed early on due to O2 sensor not being ready around 102 miles. I have done almost everything I can think of to get this thing to get happy: long freeway drives at 55-59mph on cruise control, fast freeway driving, varied load/revs city driving, extended periods of idle, multiple overnight shutdowns followed by cold starts to full warm up, etc.

No codes are present, car functions 100% as it should.

I don't drive it much and lately have been having to put miles on it just to get this darned sensor to meet whatever checks have not yet been met. Need to get this done soon in order to not get dinged for late registration with the DMV.

Any suggestions? I am using an Autel AL519 scan tool- it has never shown anything but a redX for the O2 sensor category, while everything else that appears relevant gets a green check.

 

[leres]

Trying to get my '25 5VBW smog ready. Smog check failed early on due to O2 sensor not being ready around 102 miles. I have done almost everything I can think of to get this thing to get happy: long freeway drives at 55-59mph on cruise control, fast freeway driving, varied load/revs city driving, extended periods of idle, multiple overnight shutdowns followed by cold starts to full warm up, etc.

No codes are present, car functions 100% as it should.

I don't drive it much and lately have been having to put miles on it just to get this darned sensor to meet whatever checks have not yet been met. Need to get this done soon in order to not get dinged for late registration with the DMV.

Any suggestions? I am using an Autel AL519 scan tool- it has never shown anything but a redX for the O2 sensor category, while everything else that appears relevant gets a green check.

I'm in an adjacent boat; 2025 5BW with 520 miles. My remaining missing I/M test is also O2S. (Also guessing you're also a Sewell customer and live in CA.) I had been using an Autel MS300 to retrieve I/M status but after a couple of years it go flaky so I got an Innova 5210 which I like.

This is the best reference I've found: Completing a Drive Cycle
It says:

02S Monitor: Cruise between 48 mph and 65 mph for five minutes. Try to keep the throttle steady, avoiding quick accelerations and quick decelerations. DO NOT USE CRUISE CONTROL. Cruise control'only concern is keeping the speed constant, and it will open and close the throttle plates faster than the beer refrigerator door at a frat party. This monitor normally completes quickly when the conditions are correct.

Also important:

Most manufacturers set the fuel level required to complete an OBD drive cycle between 15% and 85% full. This can be tricky due to fuel slosh. Anti-slosh programming keeps the movement of the fuel in the tank from showing on the fuel gauge. The scan tool uses real-time Fuel Level Input Sensor (FLI) numbers. If the fuel sloshes out of range, the OBD drive cycle will restart.

My plan is to (on days when I don't have any where I need to drive) hit the freeway when traffic is minimal and drive for 5.5 minutes without cruise control and try to maintain ~55 mph. Then loop around and do the same thing headed back home. Once I get below 20% fuel, I'll fill up then drive until I'm down to 80% fuel and repeat the freeway loop protocol.

It's funny, usually EVAP is the one I have trouble getting to pass, I think due to my habit of braking in neutral when coming to a full stop -- I think the EVAP test runs when the car is decelerating in gear with no throttle.

Also I've been trying to avoid constant rpm or engine load during the first 1500 miles, which appears to be at odds with running the I/M tests. And I know that some tests only run after other tests have passed so that can stretch the process out.

(Good luck!)

 

[+ManifoldPSI]

I'm in an adjacent boat; 2025 5BW with 520 miles. My remaining missing I/M test is also O2S. (Also guessing you're also a Sewell customer and live in CA.) I had been using an Autel MS300 to retrieve I/M status but after a couple of years it go flaky so I got an Innova 5210 which I like.

This is the best reference I've found: Completing a Drive Cycle
It says:

Also important:

My plan is to (on days when I don't have any where I need to drive) hit the freeway when traffic is minimal and drive for 5.5 minutes without cruise control and try to maintain ~55 mph. Then loop around and do the same thing headed back home. Once I get below 20% fuel, I'll fill up then drive until I'm down to 80% fuel and repeat the freeway loop protocol.

It's funny, usually EVAP is the one I have trouble getting to pass, I think due to my habit of braking in neutral when coming to a full stop -- I think the EVAP test runs when the car is decelerating in gear with no throttle.

Also I've been trying to avoid constant rpm or engine load during the first 1500 miles, which appears to be at odds with running the I/M tests. And I know that some tests only run after other tests have passed so that can stretch the process out.

(Good luck!)

Interesting we are in the same boat, at the same time in not so far off the same place... I am indeed in CA, but I am an outlier in that I got my car from Findlay in Henderson, NV (a la Vegas).

I can only hope it does not take until 500+ miles to satiate one last sensor check!

I will have to try the low-speed highway driving again. I did use cruise control last time, even if it was on flat ground, and I had no traffic ahead of me that caused much of any decel/accel. I also read about this series of steps online but did not read closely enough to note any requirements about cruise control being active or not, though this all seems to be fairly general guidance.

I have only fueled up once, so most of the drive time has been between 20 and 80% full, so hopefully that is not an issue.

I did see Evap go checked several days/drives ago, it has not come unchecked yet, or at least has not showed as such during the last 2 I/M readiness checks I have conducted. My style is totally opposite yours in that sense- I do a lot of engine braking, a LOT, and I am rarely on the brakes. Perhaps that helps?

FWIW I just hit 332 miles.

Guess I'll go out and try to get a drive in before traffic gets too widespread...

Thanks for the suggestions, and good luck in your attempts as well

 

[so 650]

My Blackwing and I immigrated on the same boat as you guys from the USA to California ... so I also needed to get my brand new car smogged. I followed the protocol below ... dunno if it worked, but the sensors were happy after ~ 250 miles. THere's more on the topic (including unhelpful political rants) in this thread: Out of State Purchase - Smog Test

General Motors Drive Cycle For Smog Check​

In order to get all your OBD2 monitors for your GM (Chevy, Buick, Cadillac, GMC, Pontiac, Oldsmobile) vehicle ready, please perform the following steps:

• Start the vehicle from a cold start. The time to do this is if you have not driven the vehicle for a few hours and the engine coolant temperature is less than 50 degrees F.
• Let the engine run on idle. Turn the A/C and rear defroster on. You are trying to apply electrical load to the system.
• Accelerate to 55 mph.
• Hold a steady speed of 55 mph for 3 minutes
• Let go of the accelerator and coast until the vehicle hits 20mph. Don’t apply brakes to slow down.
• Accelerate again until 60 mph.
• Hold steady for 5 minutes at 60mph for 5 minutes.
• Decellerate (coast to slow down).
• You may need to repeat steps 3-8 a few times if the battery was disconnected recently.

 

[leres]

Interesting we are in the same boat, at the same time in not so far off the same place... I am indeed in CA, but I am an outlier in that I got my car from Findlay in Henderson, NV (a la Vegas).

That is pretty amusing to me; I reached out to Findlay several times but could not get any response from them. Glad you had better luck. It would have been nice to fly to Vegas and drive home instead of spending $2.5K on an enclosed trailer... Still, I have the car with ever single option I wanted so I can't really complain.

I can only hope it does not take until 500+ miles to satiate one last sensor check!

I'm pretty sure it was due to me shifting, changing rpm, etc. several times per minute.

This is pretty interesting. I guess the theory is the O2S test (which I'm pretty sure is really a heated O2S test) needs some run cycles for the O2 sensors to be happy:

If your car is new you will fail the smog test because your O2 senor will not be ready. It will take 500-1000 miles for the sensor to be ready and each car achieves this at a different mileage.
To avoid the headache, if you fail smog and your car has under 1,000 miles you can make an appointment with the state ref, they will inspect and pass your vehicle.

I have three weeks left on my TX temporary tag, if I can't get O2S to pass within the next two weeks I think I'll try the fail and go to referee approach.

 

[rdollie]

Yikes, I forgot new cars still get smog tests in CA! We used to have them in WA State but they ended all testing 5 years ago here.

 

[+ManifoldPSI]

That is pretty amusing to me; I reached out to Findlay several times but could not get any response from them. Glad you had better luck. It would have been nice to fly to Vegas and drive home instead of spending $2.5K on an enclosed trailer... Still, I have the car with ever single option I wanted so I can't really complain.

I'm pretty sure it was due to me shifting, changing rpm, etc. several times per minute.

This is pretty interesting. I guess the theory is the O2S test (which I'm pretty sure is really a heated O2S test) needs some run cycles for the O2 sensors to be happy:

I have three weeks left on my TX temporary tag, if I can't get O2S to pass within the next two weeks I think I'll try the fail and go to referee approach.

If amusement is your thing, you really should have stuck with Findlay. Amusing does not even begin to describe the experience. I only stuck with them after a debacle with the first joke-of-a-salesman because I made a stink about said joke-of-a-salesman embodying the terrible experience I'd had with the dealership, and how they should take the chance to prove that experience is not modus operandi.

I can't imagine the rationale for needing what amounts to be dozens of cycles for the O2 sensor to get happy, but I imagine (and certainly hope) there's a valid reason for it. A GM powertrain engineer I am surely not.

The state ref approach is interesting- I'd never heard of that. Was this something someone in CA had done? I have 0 experience with the state referee system. I have asked the DMV about it a couple of times and those reps looked at me like I was speaking Swahili.

Yikes, I forgot new cars still get smog tests in CA! We used to have them in WA State but they ended all testing 5 years ago here.

Don't remind me... Nothing like having to take a brand new car with 6 miles on the odometer to a smog station to "prove" to the powers that be that it does indeed meet all state regulations... Such is the price we pay to live in California. A price that I am reminded of every second, of every minute, of every day and so on

 

[leres]

I can't imagine the rationale for needing what amounts to be dozens of cycles for the O2 sensor to get happy, but I imagine (and certainly hope) there's a valid reason for it. A GM powertrain engineer I am surely not.

Here's the service bulletin mentioned in the other thread. It sounds like the cars are not even running the O2S test until some conditions are met.

When presenting a new vehicle for the California Smog Inspection or for a Smog Inspection in another State, some vehicles with less than 1,000 miles (1,609 km), may not report an Inspection/Maintenance System Check Monitor Complete Yes status as required to Pass the Smog Inspection. This may be caused by the engine control module (ECM) disabling some of the post catalyst oxygen sensor diagnostics until a preset catalyst break-in period (which varies by model and vehicle) has been completed.

It also says:

In California, the customer can call 1-800-622-7733 to make an appointment with the California Bureau of Automotive Repair (BAR) Referee Scheduling Center in order to get a waiver from the Oxygen Sensor Monitor Complete requirement.

I tried calling and eventually was told I needed to go get a fail and then I could call back and get a waiver.

Page 3 of the service bulletin has a screen grab of GDS 2 that shows O2S break-in parameters, e.g. HO2S 1 Break-In Period Remaining, a percentage. I tried to find that parameter on my car (I have access to GDS 2) but I don't see it for my car.

 

[+ManifoldPSI]

My Blackwing and I immigrated on the same boat as you guys from the USA to California ... so I also needed to get my brand new car smogged. I followed the protocol below ... dunno if it worked, but the sensors were happy after ~ 250 miles. THere's more on the topic (including unhelpful political rants) in this thread: Out of State Purchase - Smog Test

General Motors Drive Cycle For Smog Check​

In order to get all your OBD2 monitors for your GM (Chevy, Buick, Cadillac, GMC, Pontiac, Oldsmobile) vehicle ready, please perform the following steps:

• Start the vehicle from a cold start. The time to do this is if you have not driven the vehicle for a few hours and the engine coolant temperature is less than 50 degrees F.
• Let the engine run on idle. Turn the A/C and rear defroster on. You are trying to apply electrical load to the system.
• Accelerate to 55 mph.
• Hold a steady speed of 55 mph for 3 minutes
• Let go of the accelerator and coast until the vehicle hits 20mph. Don’t apply brakes to slow down.
• Accelerate again until 60 mph.
• Hold steady for 5 minutes at 60mph for 5 minutes.
• Decellerate (coast to slow down).
• You may need to repeat steps 3-8 a few times if the battery was disconnected recently.

Thanks for posting this. Hope the sub 50F step is not rigid, that temperature ain't gonna happen for months around here...

Here's the service bulletin mentioned in the other thread. It sounds like the cars are not even running the O2S test until some conditions are met.

It also says:

I tried calling and eventually was told I needed to go get a fail and then I could call back and get a waiver.

Page 3 of the service bulletin has a screen grab of GDS 2 that shows O2S break-in parameters, e.g. HO2S 1 Break-In Period Remaining, a percentage. I tried to find that parameter on my car (I have access to GDS 2) but I don't see it for my car.

It sure would be nice to have added details from the car's onboard modules pertaining to I/M readiness so that a user could focus on specific areas to satisfy. Granular, sure, but still would be helpful in cases like these. Something like a FAQ even. Does GDS help with that?

Interesting. I called about 8:30a today and was told that waivers are not available for sensors failing to be ready, but that someone from the BAR would reach out to "provide guidance", whatever that means.

The part about the needing to fail first makes sense, but the disparity between what you were told and what I was told does not... Then again, what should I expect from the DMV? Consistent and helpful information? Bah.

 

[leres]

I got my smog check, as expected it was a fail. Hours later I do not see the vin listed on the BAR site. Once it makes its way into the database I should be able to call the state and get a waiver.

I also got a vin inspection (El Cerrito, CA). Pro tip: you do not need an appointment or to even go inside. Just pull up to the drive through and someone with a clipboard will come out and help you. In my case, the left lane was for vehicle inspections and the right lane was for driver tests. (I guess you might need an appointment if you need a fresh temporary tag or to register the car but it's my understanding that Sewell will do all of that for me.)