C6 Z06 tune for O2 sensor error

[jkg2101]

Hello - need some advice. I have a totally stock 08 Z06 corvette. i have a problem where the engine often gives a 0420 code - O2 sensor error - this is a known problem with 07 and 08 Z06, and GM has a revised calibration for the computer that eliminates the problem. I dont really want to pay the dealer to do this for me, (i dont even want my car in their hands if it was free) and my car is long out of warranty. Does anyone have a suggestion how I might do this myself? i have some experience with hp tuners, and I own the hardware and software. just not sure if this kind of parameter is available in the tuning software

i would like the car to still pass New York inspection, so it needs to give a good status for the O2 sensors
justin

[jkg2101]

If I just go to the editor and under 'Engine Diagnostics" subheading "DTC", i can look up P0420 and P0430.
If I was to change the action for these codes from "MIL on first error" to "no Error reported", this would solve the problem of the check engine light and allow the car to pass emissions. Is that correct? I understand this might not be legal with the state inspection process

[BROCK01]

Dodgy but sure, just turn the MIL Light off if you dont care about the error itself

[07GTS]

do u know what the factory do to fix it ? if its just a widening of the threshold before it triggers then u may be able to just raise/lower the threshold of the error so it dosnt set but still works for the tests, oxygen sensor exhaust in engine diag tab may help it with the rear 02's

[blindsquirrel]

P0420 is not 'O2 sensor error', it's Catalyst Efficiency.

Circuit/System Description

Important: A new converter with less than 100 miles on it may set DTC P0420 or P0430 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.

A 3-way catalytic converter (TWC) controls emissions by converting hydrocarbons (HC) and carbon monoxide (CO) into carbon dioxide (CO2), and oxides of nitrogen (NOx) into nitrogen. The TWC also stores oxygen. When the listed idle conditions follow the listed driving conditions the Catalyst System Efficiency test will run. The engine control module (ECM) monitors this oxygen storage capacity by comparing the pre and post-catalyst oxygen sensor signals while adding and subtracting fuel during specific idle conditions. The ECM compares the pre and post-catalyst oxygen sensor signals to determine if the oxygen storage capacity of the catalyst is degraded.

The only thing you can do in (older versions of) HP Tuners is completely disable the catalyst monitoring (which would fail your NYS inspection just the same as if you'd done nothing), there are no fields to adjust the thresholds the ECM uses to decide if the cats pass or fail.

The solution is a thing that you do not want to do, for whatever reason.
screenshot.04-01-2023 04.55.02.png

There are humans on this planet other than the dealer who can flash GM modules these days, you know. It's fairly common for decent independent garages to do their own reprogramming.

[TheMechanic]

As blindsquirrel said jut pick yourself up a MDI 2 module, use your laptop and install Techline Connect, or just SPS, https://www.acdelcotds.com/subscriptions Pay the subscription cost and program it yourself. Easy Peezy.

[jkg2101]

As blindsquirrel said jut pick yourself up a MDI 2 module, use your laptop and install Techline Connect, or just SPS, https://www.acdelcotds.com/subscriptions Pay the subscription cost and program it yourself. Easy Peezy.

thanks for all the advice - i was wondering if i could use hptuners hardware (MPVI2) to correct the problem on my own, either by adjusting the sensor parameters, or disabling the error message, or installing the upgraded GM tune.
I wonder if the stock Z06 tune from a later year already has this incorporated into it - i could just reflash using hptuners. Or i could adjust the error limits on the 02 sensor if I could find where to do that, but i dont think hptuners has that option.

i do have the option of disabling the error reporting for this particular code - i didnt think that would prevent the car from passing state inspection?

[blindsquirrel]

There are 8 segments in the Gen 4 ECM, but HP Tuners only reads/writes 6 of them. So changing the OS in HPT is a no-go. (I know this is not a platform swap-type rewrite, but those two unwriteable segments are still different between old OS and new OS, so... no.)

The inspection station will be able to tell which monitors your vehicle is supposed to have, so if you disable catalyst monitoring it will still fail just the same as if it had catalyst codes or the catalyst monitors showing as 'not completed'. Just get it flashed by someone who can do GM SPS-type stuff.

[jkg2101]

There are 8 segments in the Gen 4 ECM, but HP Tuners only reads/writes 6 of them. So changing the OS in HPT is a no-go. (I know this is not a platform swap-type rewrite, but those two unwriteable segments are still different between old OS and new OS, so... no.)

The inspection station will be able to tell which monitors your vehicle is supposed to have, so if you disable catalyst monitoring it will still fail just the same as if it had catalyst codes or the catalyst monitors showing as 'not completed'. Just get it flashed by someone who can do GM SPS-type stuff.

Thanks for the input. sorry, but i am a little slow at some of the terminology. So, if I set the computer to not report an error with code p0430 (O2 sensor error), (so I am turning off error reporting but not turning off the monitoring?) the check engine light will not come on, and then drive the car normally so the computer thinks it is ready for an inspection, somehow the state inspection computer will know? i dont know the details of the computers well enough, but i had assumed if the computer is programmed to not do anything if the code is detected, then there will be no check engine light and no problem with state inspection computer. sounds like that is not correct

[07GTS]

the ecu runs a startup test u can see the log of it in the scanner, if the sensor is not working properly it wont show as ''ready'' use the scanner to turn key on and go to the engine symbol and it should show what tests pass, if all pass stock then all have to pass the inspection to show the emission system is working properly

[That_guy]

One particular issue I've seen with C6 Z's especially is, if they set any kind of MIL light for something emissions related it will need to see that sensor functioning or reading correctly again before it'll ever let that MIL light come out of pending status. You can't force them to ignore the MIL once it's been set, even setting them to with a tune no MIL. It will still come back until the PCM's sees that particular sensor or problem functioning properly again. This is for HPTuners capabilities that is. You can go in with the MDI and try to download the newest cal for your PCM however if the OS on your PCM is the same as the latest update, it will do nothing for your MIL light by updating. Been there too. LOL

[blindsquirrel]

I think the permanent code thing only started in 2010 or 2011, and that was across the whole range. Not just GM, either.