P0420 reset after 690 to 750 miles
Vehicle come in with P0420 monitored O2 sensors , rear 02 never leveled out . Checked plugs and replace due to mileage (yes AC/Delco). Replaced Cat, Front and rear 02 sensor, Cat is Aftermarket, never had a problem with this brand , front and rear 02s are NTK.
Drove vehicle for customer to set monitors and pass emissions mode 6 data for catalyst monitor is pass value .2126 , min .18 ,max 3.9998.
Customer daughter drove vehicle back to school and now a month later light back on for P0420, looked at freeze data and mode 6 of catalyst monitor shows failed but my values are different. fail value .2968, min .2998 ,max 3.9998. Is this a GM software glitch or am i just missing something . i have attached both vehicle reports for mode 6 and freeze data for pass and fail.
I have had a number of customers call me on this one for updates. Some had updates, some did not. The ultimate solution has been to replace with OEM catalyst. The aftermarket missed the mark on this vehicle. You may want to check the calibration and see if it is up to date. TIS (gm.com) Use the TIS link and type in the VIN. Check against readings in scan tool. Generic OBD should…
You will need to install an OE converter. I have tried many aftermarket options and they all eventually set a 420/430, usually within the first few drive cycles. It is not worth the money or effort to use aftermarket converter options.
The Mode $06 results you found are not a bug, just a function of the way this Catalyst monitor displays results. We just went through this on a '14 Cruze 1.4L of our own. Installed an aftermarket converter, came back after a couple hundred miles. OE cat fixed it.
ive replaced both cats on a V Engine with aftermarket and had one pass and one fail. might give warranty a shot but likely it will need OE. pcm update might widen the parameters for cat efficiency too
If you verified that there are no air leaks in front of the cat, I would replace the cat with a CARB certified one or OEM. There are only a handful of aftermarket cats available for that platform. ssl.arb.ca.gov/AftermarketPar…
Inspect for exhaust leaks, lambda read at tail pipe for proper fuel control verification.
Install OE cat and 02 sensors before going any further
Hi Scott, Have them change to a higher quality fuel station such as Exxon or Shell. I have had this issue with several vehicles and fuel quality was the related factor in all of them. Pull a fuel sample and test for contamination, separation and/or a high Ethanol content. CAT's are possible, but verify no upstream leaks exist. It seems most common on these very small engine compacts, that the…
These 1.4 motor ecms do cat diagnostics at idle. Graph up and down o2s at idle. Oem cat is the solution.
Performed smoke test on exhaust , all good , fuel trim in freeze data looks good, the girl fills up at same station and travels same path everyday to and from local college. Replace with Dealer Cat late today. Good thing I still had original from car , they wanted $400 core and it had to be OEM core . Will do test drive and look at 02s at idle and warm up . BTW am I reading GMs site, I have to…
It is only $40 per vehicle through gm. When they went to tech line connect it got A bit confusing. as long as you launch from google chrome after you pit chase your $40 subscription everything will load just fine. Your tds user name and password will automatically carry over to tech line connect.
Check your Cal IDs against GM TIS before spending the time getting Techline set up. tis2web.service.gm.com/tis2web
Looks like my calibration IDs match , I was just asking for future usage. Thank all of you for advice and help, will update post once readiness monitors pass and customer reports back. Scott
As multiple others have stated, get an OE cat. Even the dealers had some faulty cats right out of the box, due to a build error on the early replacements. But, it'll repair the issue.
Replaced Cat last week customer will bring back Friday for me to scan and look at monitors
On the Cruze, all you have to do, is to use a scanner with enhanced software, and look at Exhaust Aftertreatment PIDs. You can even watch it pass in real time, and know when it's actually being tested. No need to wait for the customer to bring it back. A good catalyst on these, will pass in less than ten miles.
Yes , that was the plan but the customer had to have the vehicle to get back to class the day I had it , I had a window of 1 hour to get the cat replace it and get her on the road .
Customer is happy that light is off , and hasn't come back on in 600 miles as of now . Thank all of you for advise and direction. Scott