Nissan 370Z Forum - View Single Post

JWillis72 · 07-31-2014, 07:08 AM

I had my car at Sebring this weekend and it ran great but monday on my way to work my check engine light came on showing two P4020 codes "Catalyst System Efficiency Below Threshold (Bank 1)". At the track I was running 93 octane with no ethanol in it and thought that might be causing it so I ran it down to 1/4 tank and filled it back up but I'm still getting the code. Anyone ever seen this happen?

07-31-2014, 07:08 AM	#1 (permalink)
JWillis72 A True Z Fanatic Join Date: Sep 2013 Location: Fort Myers FL Posts: 2,002 Drives: 2009 370Z yellow 7AT Rep Power: 44	Stillen supercharger getting P4020 cod2 I had my car at Sebring this weekend and it ran great but monday on my way to work my check engine light came on showing two P4020 codes "Catalyst System Efficiency Below Threshold (Bank 1)". At the track I was running 93 octane with no ethanol in it and thought that might be causing it so I ran it down to 1/4 tank and filled it back up but I'm still getting the code. Anyone ever seen this happen?