Catalyst/02 sensors not ready for emissions tests

[RTR077]

I have been trying to figure out how to fix this problem, but I am out of ideas. I cannot pass emissions testing in my county without the smog sensors active, yet they refuse to 'ready' up. I have driven the car a few hundred miles, tried 02 spacers on the downstream sensors and had it in my with my tuner, but the problem remains.

The car had Kooks headers and green cats installed in December and then dyno tuned in February. This is the first year it needed emissions testing.

My fall back plan is to return to stock headers and cats if need be. My tuner doesn't seem to want to touch it and has said they cannot play with emissions related software.

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[engineermike]

Won’t reach ready status or got an emissions code p0420/30?

If it won’t reach ready status, it usually means the tuner turned off something in the tune. Otherwise it should pass or fail. How are you at data logging?

 

[RTR077]

Won't reach ready status on 02 sensor, catalyst and 02 sensor heater.

I've never datalogged, but I am willing to learn

 

[engineermike]

You can log all 4 o2 sensors and capture the pcm performing a test. Once the engine warms up and you are at steady state driving, it will initiate a test. The fuel trims all lock to 0, and you’ll see the front/wideband lambda start cycling, left and right being opposites. The rear o2 voltage should stay fairly constant, switching 1 or 2 times through the test. If the cats are bad, the rears will switch with the fronts.

However, with your other issues I would investigate the o2 sensors and connections themselves, as well.

 

[engineermike]

Here ya go:

https://www.mustang6g.com/forums/threads/roush-5-0-cat-failure-caught-in-the-act.203550/

First post shows how to log for cat function.

 

[junits15]

Bet you a crisp $5 bill that you have FAOSC disabled in that tune. What mods are on the car?

If its just basic stuff you could run a stock tune with spacers until you pass then flash back

 

[engineermike]

Bet you a crisp $5 bill that you have FAOSC disabled in that tune. What mods are on the car?

I would have bet $20 if he hadn’t said something about the tuner not wanting to mess with emissions stuff.

 

[NightmareMoon]

Have you tried to follow the drive cycle procedures? If not, its really not suprising that it hasnt readied up in only 200 miles.

Make sure you have no codes, follow the drive cycle procedure closely until each stage readies. A couple of them are kind of a PITA. I’d always get stuck on the one where you have to drive a constant speed for a while, very few of the roads around here are that speed limit, and dont’t have a ton of traffic lights. Took me like 6mo to ready up after my last tune because my driving patterns just dont match the drive cycle procedure.

 

[RTR077]

Have you tried to follow the drive cycle procedures? If not, its really not suprising that it hasnt readied up in only 200 miles.

Make sure you have no codes, follow the drive cycle procedure closely until each stage readies. A couple of them are kind of a PITA. I’d always get stuck on the one where you have to drive a constant speed for a while, very few of the roads around here are that speed limit, and dont’t have a ton of traffic lights. Took me like 6mo to ready up after my last tune because my driving patterns just dont match the drive cycle procedure.

I haven't in all honestly because of my stubbornness. I have read others that have w/o change and the logic just doesn't ring true for me. That said, I will try it because its getting me down and my car is technically not road legal.

 

[NightmareMoon]

I haven't in all honestly because of my stubbornness. I have read others that have w/o change and the logic just doesn't ring true for me. That said, I will try it because its getting me down and my car is technically not road legal.

Well the emissions systems are looking for a specific set of conditions, temperatures, miles, at specific speeds. Sometimes speeding up and slowing down a certain number of times, etc.

If you never do those things, it won't ever ready up. The 02 sensors are like the last step.

Here's the drive cycle procedure for the 2016 car. Depending on your mods and tune, some of other things people mention above may also be factors.

https://www.mustang6g.com/forums/at...top, idle for,acceleration and cruise 3 times.

I run an OBDII reader and phone app to help track the steps as it clears each. You should be able to figure out what step you're stuck on with an OBDII reader/app and that drive cycle procedure.

 

[RTR077]

I have definitely followed this step, yet the H02S is still not ready.

 

[NightmareMoon]

what about the Catalyst step? IIRC the O2 sensors won't ready until basically everything is ready

 

[junits15]

I would have bet $20 if he hadn’t said something about the tuner not wanting to mess with emissions stuff.

Agree, truthfully it's just my first guess for things that are commonly changed that cause this behavior.

I'm sure there's other things that can cause this behavior, but I don't know enough to guess farther than FAOSC.

 

[Goterr0r]

If you're sure its not turned off in the tune, hard reset your battery. Leave it disconnected for a while and start the process over. I had the same thing happen and couldn't get the drive cycles to go until i fully reset everything by leaving the battery off. Something to try if you haven't already.

 

[RTR077]

Update:

Tuner states FAOSC is enabled

I disconnected the battery for a few days and removed the 02 spacers.

Now I get a P0155 code: 02 sensor heater circuit bank 2 sensor 1

My next move will be to replace the sensors. Which side? Any other ideas?

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