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・Save up to 30%

Get a quote

What others are asking

Q: My gas mileage has dropped to 22 mpg, what could be the cause?

When a vehicle gets poor fuel economy, it's typically due to an electrical sensor that is faulty, such as the oxygen sensors, the air fuel ratio sensor, dirty fuel injectors, or the throttle body being dirty. Driving habits can also...

Q: Turning over but won't start

Hi there: Quite often the type of issue you're describing is caused by a fuel restriction or emissions component issue. Some of the particular parts that could be causing this include the EGR valve, O2 or air to fuel ratio...

Q: Are all the motor mounts the same on the sides and in the front?

No, they aren't. Typically there are four main mounts that support the motor and the transmission. Depending on the parts source you buy from, it is important to be specific about the position of the mount. Mounts may or may...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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 Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.