Thread: Check Engine Lights

I have had the P420 code pop up three times since I owned the car. Once about 5 months ago, for reasons unknown, the other two about 3 months, and two months ago, both after hitting a hard pot hole or bump I didnt notice.. Arlington has ****ty roads. The last time, about 2 weeks ago, was while the car was idling warm foor about 5 minutes it tripped.... not sure if it truly is the cat, or something else... wouldnt it come on more often if it was the cat? should I check my o2 sensors or no? just really hoping its not the cat.
The P0440 came up twice... both under a semi hard braking manuever, I know its commonly a gas cap, but what other things can it likely be on this car?
Any feed back is welcomed.

Added: Also wondering if its a o2 sensor because the best I've every got out of a tank of gas is 340miles with a light foot. And thats bone dry 17.2 gallon fill up. Ive heard bad o2's cause bad MPGs.

bump

Had a new code today... I had a P0442 today. Evaporative Emission System Leak Detected (small) Could this be the o2 sensor as well?

Try this.
P0420 Error Code: Catalyst System Efficiency Below Threshold (Bank 1)
OBD-II Trouble Code: P0442 Evaporative Emission Control System Leak Detected (small leak)

I should have read up more on the 0442 code, was in a hurry to leave for somewhere so I didnt research it. Guess I'll be getting a gas cap.
Also is a Bosch o2 sensor just as good as AcDelco.. normally I'd go with a stock part on this type thing.. but on Rockauto, the Bosch one is cheaper.

I've heard bad things about bosch

could be evap canister if not gas cap

Originally Posted by SoergBot

could be evap canister if not gas cap

Where is the location of the Evap Canister?

Originally Posted by dsmuts

I've heard bad things about bosch

See, I've heard bad things about Bosch plugs and wires, but great things about them in other vehicles.. so i wasn't sure about the o2 sensers