P CODES (POWERTRAIN) P0400 - P0499

I Have Changed The Gas Cap In My Car But My Engine Light Is Still On. Its A 99 Mercury Cougar. Could It Be Bad Gas From What I Filled The...

97 F150 Has Code 402. I Replaced The Valve And Checked For Plugged Lines And The Code Comes Back. The Vehicle Runs Fine.

The Piece That The Hose Connects To Broke Off And I'm Trying To Figure Out What It’s Called So I Can Replace It Or If There’s...

Is There A Picture Of Where The Sensor Is On The Fuel Tank, A Diagram Or Something

Engine Performance Problem 1998 Chevy Silverado V8 Four Wheel Drive Automatic Thank You For Your Response. It Helped Id The Part That...

Catalyst System Efficiency Below Threshold Bank 2. What Is The Likelyhood That This Is Just The Oxygen Sensor Gone Bad Versus The Front/...

I Found Out That The Code P 0455 Means Evaporative Emission Control System Leak Detected. Could Someone Please Explain To Me What This...

Tried Cleaning Both Idle Control Valve & Egr Valve As Y Ou Suggested. Did Not Help, Both Were Fairly Clean And Functional. Also If Anyone...

This Code Is The Only One That Keeps Appearing Pending Twice In My Car, Now It Makes A Loud Funny Vibration Noise When You First Press The...

Comes Up As Evap Monitor Leak (small) Detected Where Do I Look For This And How Do I Fix? Any Help Is Appreciated, Thank You.