Questions & Answers for: Chevrolet TrailBlazer p0420 code

code and it read P0420 and P0128. Any ideas what this means? You don't mention any vehicle specific info, but the codes read as follows: P0420 - "Catalyst Efficiency Below Threshold (Bank 1)" P0128 -

...every time. Sometimes it takes up to 5 tries to start. The codes I'm getting are P0106, P0420, P0410, &P0128. I'm on a budget so fixing them all at o Many of the codes have

...code p0420 what is code p0420 i change the oxigen censor the upper one and the lower one.. i chenge the fuel filter and the air filter.. still getting code p0420 Is your engine temperature at 210 ...

...code (420). If the cat is bad, then only P0420. If the cam is bad it will set a cam code, but the ECM will go in default mode and still run the engine. Bad gas mileage, yes, But will still run. Best ...