I have a 2000 Pontiac Sun fire I have an error cod of 420 what do all this mean and how to fix the problem?

Answer 1

P0420 (not just sijmply "420") is; Catalyst System Efficiency Below Threshold (Bank 1).

What this means is the Oxygen Sensor after the catalytic converter (downstream O2 sensor) is detecting that the catalytic converter is not functioning within specifications.

There are a lot of things that can cause this. Use of the wrong grade of fuel (87 instead of 92) is common, but does not apply to your vehicle. A malfunctioning downstream O2 sensor is another. Coolant temp sensor malfunctions, poor spark and a couple of other things can also cause it. GM will have a specific series of tests that need to be run in connection with this code on this vehicle. My first recommendation though would be to have the code cleared and see if it comes back. One of the alternatives is that it could have been a temporary glitch that cleared itself.

Answer 2

Cat system out of range. Usually means the O² sensor is bad, and probably on bank one. Sensors aren't bad to change, unplug one wire and they screw out. Could also be catalytic converter problems.

Answer 3

Power Steering Control Module.

first disconnect the negative terminal of the battery for more than 10 seconds.( to erase the code)
if the code pop up again then replace the control module. by a technician, due to the part location .
doing it Yourself may cause more bad than good.

Answer 4

you are missing a digit on that error code, does it start with zero or four.?