P0420 question. Please help! - Toyota FJ Cruiser Forum
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post #1 of 1 (permalink) Old 03-18-2019, 12:13 PM Thread Starter
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P0420 question. Please help!

So, I have only the p0420 code right now and have been using a blue driver (obd 2 scanner) to read all my info. The scanner shows me the cat temps and both banks have just about the exact same temperatures (pictured below) so i'm thinking it isn't my cat. Am I correct in assuming this? From looking at the O2 sensor voltage readings and the fuel trims, the only thing that seems to be off is my long term fuel trim in bank 2. It reads 11.7% (and seems to only increase) while bank 1 only reads 2.3% which is a decrease from where it previously was 10 minutes ago at 3.9%. The only reason I think it IS my cat is that the downstream sensor voltage is fluctuating up and down. Also, if it makes a difference, all this info is with the p0420 code erased. Someone please help. It's a 2007 with roughly 140k miles on it. A few months ago, I was getting a p0420, p0101, p0171, p0174. Then p0420 went away leaving the other 3 codes. After an advance auto MAF replacement sensor, I got a p0300 and p0306. I then got a denso OEM MAF sensor and all previous codes went away but I got rich codes on both banks and I know thhe Fj was running extremely rich. I found out that a toyota technician had bumped one of the air filter rings into the intake tube and was touching the MAF so I removed it and the rich codes went away. I had no codes for a full day of driving and then the p0420 code returned which brings us to today. I've been driving with it for about a month and a half. All help is appreciated.
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Last edited by chasitek; 03-18-2019 at 10:07 PM.
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