Skip the auto shop - Our mechanics make house calls

Q: O2 sensor failed

asked by on

I let my truck sit over the weekend and it won't start. The oil level is fine, but the light did come on, telling me to change it, before I parked it. I am also losing coolant.

A: Hi there. A p0420 usually means the catalyt...

Hi there. A p0420 usually means the catalytic convert is not performing as well as it needs to. Over time, the catalytic converters fill up with carbon and and will not filter out the exhaust gas as efficiently as they should, which means a replacement is needed. I would recommend having a technician, like one from YourMechanic, inspect for any error codes and replace the catalytic converter if necessary.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Bosch's Website Says My Car Can Accept a Universal O2 Sensor

The definitive answer is "maybe" But with late model cars, I prefer to use the original equipment. A universal sensor, if wired correctly will not damage your system, but it also might not solve your problem. The ECM in your...

Q: Is there any simple way to diagnose why my AC won't blow cold?

Hello. I will help you with this issue. If the a/c compressor is NOT running (and thus NOT creating suction in the refrigerant piping on the low side) and you apply a gauge to measure system pressure on the low...

Q: Brake pedal has no resistance

This is a very dangerous situation as the braking system is one of the most important safety features of a vehicle. Have a brake inspection carried out by a qualified technician such as the ones here at YourMechanic to look...

Related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.