[Trafresh]

Hey Everyone,

Bran new to the forum. I didn't realize i had an account so this is my first post. I recently had my traverse brought in to the dealership to perform the 50K tune up. They replaced the air fileter, cain filter, they drained and replaced the transmission fluid, performed a brake flush and crankcase service. Its been over a month now and i recently had the check engine light populate the other week. Had Ons star perform the diagnostics while i was on the road. I was told the code returned was P0420. I figured it was something to do with the gas tank pressure as it occurred frequently on my 08' Cadillac CTS.

A few days later and of course, it seemed to clear itself, then a few days ago it reappeared. Then went away again earlier this morning. I decided to use my OBD scanner and it came to return the same P0420 code. I then went to check the freeze frame data and came across the following readings. Would anyone be able to elaborate more on this data? Im almost certain it can be an O2 Censor but just was curious to what all this data translates to. Any information is greatly appreciated.

DTCFRZF ---------: P0420
FUEALSYS1 ------: OL-Drive
FUEALSYS2 ------: N/A
LOAD_PCT(%) ----: 23.5
EXT (°C) -----------: 82
SHRTFT1(%) ------: 0.0
LONGFT1(%) ------: -10.9
SHRTFT2(%) ------: 0.0
LONGFT2(%) ------: -11.7
FRP (KPa) ----------: 399
MAP (KPa) ---------: 26
RPM (/min) --------: 1119
VSS (km/h) --------: 62
SPARKADV (°) -----: -3
IAT (°C) -------------: 23
MAF (g/s) -----------: 5.33
TP (%) --------------: 17.6
02B1S1 (V) ---------: 0.000
SHRTFTB1S1 (%) -: 0.0
O2B1S2 (V) --------: 0.225
02B1S1 (V) ---------: 0.000
SHRTFTB3S1 (%) -: 0.0
02B3S2 (V) ---------: 0.870
RUNTM (sec) -------: 289
FRP (KPa) -----------: 3400.0
EVAP_PCT (%) -----: 0.0
FLI (%) --------------: 91.0
WARM_UPS --------: 255
CLR_DIST (km) -----: 65535
EVAP_VP (Pa) -------: 25.00
BARO (KPa) ---------: 100
CATEMP11 (°C) -----: 771.00
CATEMP21 (°C) -----: 771.00
VPWP (V) ------------: 14.583
LOAD_ABS (%) ------: 15.1
EQ_RAT --------------: 0.999
TP_R (%) -------------: 7.5
AAT (°C) --------------: 11
TP_B (%) -------------: 17.6
APP_D (%) -----------: 19.6
APP_E (%) -----------: 9.8
TAC_PCT (%) --------: 10.6

 

[repairman54]

P0420 is an inefficient catalytic convertor code.
O2B1S1 is at zero, BUT a freeze frame can be deceiving as some readings have to be observed in real time like a front O2 sensor.

 

[Trafresh]

Ah okay. for what its worth. I noticed a huge decline in power when accelerating. Planning to bring it back to the dealership. Its only at 55K miles. Shouldn't have any issues so early. I did take it to them earlier last month for the scheduled 50K service. I dont see them listing of changing the spark plugs. may be a culprit?

 

[RandyMan]

Spark plugs are replaced at 97,500 miles per maintenance schedules for the 3.6L. So they should still be good. Like repairman54 said, it needs live data diagnosis to determine what is tripping the code.

-RandyMan

 

[Trafresh]

Thanks everyone. I tired taking it to the dealership this morning but was asked to come back first thing Monday morning. I'll let everyone know. Im barely at 55K miles so it should be still covered under warranty if its the drivetrain.

 

[electbc]

Do you use Toptier gasoline? These codes do come up in my Equinox, my daughter uses the cheapest gas she can get. A P420 came up when I was driving with her Jan22 and another one came up this March. I put in a bottle of Techron and it went away. I tell her to use a bottle of Techron every two tankfulls and it seems to take care of it.

 

[Trafresh]

No i usually use mid-grade but now that you mentioned it, i'll start using top tiered

 

[Watthour]

Try to determine the actual source of the fuel you are using. Sometimes it isn't the fuel, but the distribution point (retail station). That "top-tier" fuel is (statistically) very likely supplied from the same place that the cut-rate stations use. Do you know where the pipelines and tank farms are located in your region? That's a good starting point.

 

[Trafresh]

Was able to drop it off this morning. Turned out to be the Catalytic Converter Assembly. Wasn't pulling any codes until i asked the mechanic to test drive it himself. Mentioned it was covered by warranty since its only at 55K miles. We'll see how it runs once i get it back tomorrow. Thanks everyone for their input.

 

[Trafresh]

Got the traverse back a few days ago.Fortunately, it was covered under warranty. So far so good. About to take a trip down to SoCal later this week. So we'll see how that goes. 🤞