P0420 reset after 690 to 750 miles

Scott Technician Tennessee Posted   Latest   Edited  
Resolved
Emissions
2014 Chevrolet Cruze LTZ 1.4L (B LUV) 6-spd (6T40) — 1G1PG5SB8E7274205
P0420 — Catalyst System Efficiency Below Threshold Bank 1
Recodes After Passing And Then Driving Roughly 500 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.

thank you 

Scott

0
Interesting
Rudy Technician
Utah
Rudy
 

Install an OE or CARB certified cat.

+5
Ð Awarded
Agree
Stephen Owner/Technician
California
Stephen
 

Use OEM cats.

+1
Ð Awarded
Michael Mobile Technician
Utah
Michael
 

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…

0
Ð Awarded
Scott Technician
Minnesota
Scott
 

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.

0
Ð Awarded
Tyler Technician
Kansas
Tyler
 

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.

0
Ð Awarded
Cody Diagnostician
Illinois
Cody
 

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

0
Ð Awarded
Danny Technician
California
Danny
 

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…

+1
Ð Awarded
Agree
Helpful
Rod Diagnostician
California
Rod
 

Inspect for exhaust leaks, lambda read at tail pipe for proper fuel control verification.

+1
Ð Awarded
Caleb Diagnostician
Indiana
Caleb
 

Install OE cat and 02 sensors before going any further

0
Ð Awarded
Glenn Owner/Technician
Texas
Glenn
 

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…

0
Ð Awarded
Frank Manager
Tennessee
Frank
 

These 1.4 motor ecms do cat diagnostics at idle. Graph up and down o2s at idle. Oem cat is the solution.

0
Ð Awarded
Agree
Scott Technician
Tennessee
Scott
 

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…

0
Ð Awarded
Scott Technician
Minnesota
Scott
 

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.

0
Ð Awarded
Tyler Technician
Kansas
Tyler
 

Check your Cal IDs against GM TIS before spending the time getting Techline set up. tis2web​.​service​.​gm​.​com/tis2web

0
Ð Awarded
Scott Technician
Tennessee
Scott
 

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

0
Ð Awarded
Timothy Owner/Technician
Wisconsin
Timothy
 

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.

0
Ð Awarded
Scott Technician
Tennessee
Scott
 

Replaced Cat last week customer will bring back Friday for me to scan and look at monitors

0
Ð Awarded
Timothy Owner/Technician
Wisconsin
Timothy
 

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.

0
Ð Awarded
Scott Technician
Tennessee
Scott
 

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 .

0
Ð Awarded
Scott Technician
Tennessee
Scott
 

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

0
Ð Awarded
Scott Technician
Tennessee
Scott Resolution
   

Vehicle fixed thanks for all the help

0
Resolution Ð Awarded