P0431 and P0421 codes?

Car Has Check Engine Light On. I Changed The Cat On The Bottom Of The Car But Still Has Light On. I Understand That It Can Be A O2 Sensor...

Obd Code Po421 Is Registering On My Car. According To What I'd Read It Means The "warm Up Catalyst Efficiency Is Below Threshold Bank 1...

I've Had This Code Come Up Three Times Since I've Had The Car Which Has Been About 5 Months. When I Got It The Light Was On. After Replacing...

Hi, I Have A P0403 On My Car, And I Can't Seem To Get Rid Of It. The Car Really Isn't Showing Any Signs Of A Problem. Gas Millage Is...

Po400 Is The Code That I Am Getting. I Replaced My Egr Valve And Check The Vacuum Hoses. My Next Step Is The Egr Hole Which Is Behind The...