Q: Service engine light is on

asked by on December 27, 2016

I'm trying to figure out if i need to replace the catalytic converter or is it the oxygen sensor. Should i replace the oxygen sensor first and if so how do i know which one to replace because my car has two oxygen sensors????

My car has 150000 miles.
My car has an automatic transmission.

Check Engine Light is on Inspection $79.99 - $99.99 Get a Quote

Hi There, Generally when the check engine light is on, it will register a code in the computer indicating which oxygen sensor is bad. i would suggest starting with replacing oxygen sensors first as this is much more common to fail than a catalytic converter and is much less expensive to repair. I would recommend having a professional from YourMechanic come to your location to diagnose using a scanning tool which should more specifically narrow down what the cause for the check engine light might be.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

My coolant light keeps coming on in my Volvo XC90 and I notice that I keep having to fill it because it keeps going below the max

It sounds like the leaking may be potentially be near or at the water pump, resulting in the coolant leaking onto the belt and causing the squeaking sound. The other possibility may be that the squeaking may be indicating that...

i have a 1994 z28 and i did a head gasket replacement for some blown head gaskets. I then tried changing the timing gears and when

Hi there. It really depends on the location of the motor (meaning if it's installed in the vehicle or loose and on an engine stand), that would factor into the price and whether this is a project one of our...

Shift from 'drive' to 'L' while the car is in motion

Hey there. In general, "yes", you can do this. Most automatic transmissions allow this, within limits of acceptable engine speed. But this will accelerate transmission internal clutch wear, with shock loads on the axles, CV joints, engine, and differential. Modern...

Clicking noise with steering wheel - 2011 Hyundai Sonata

There are three or more steering system recalls that may pertain to this vehicle. One is for the steering knuckle that was not made correct and not tightened correct during assembly and the loss of steering may be possible. The...

Car wont go into gear - 2010 Ford Mustang

Hi and thanks for contacting YourMechanic. The issue with the gear shifter is the shifter itself. The shifter has broken and is not engaged with the synchronizers within the transmission. This is why the shifter is very smooth and moves...

A lot of oil is leaking out of the oil filter. It just pours out.

Hello. If oil is leaking from your oil filter, then either the filter is not being installed correctly or the oil filter housing is damaged. Most oil filters use a rubber gasket to seal the oil in the engine. If...

I have a crack in my bumper. Do I need to replace the whole thing?

Assuming the crack is more than just a crack in the paint, I would say yes, and here is why. It will cost more money to repair the bumper than it will to simply replace it. There are many quality...

Clutch doesn't come back up, 2001 Toyota Celica

Hey there, thanks for writing in about your 2001 Toyota Celica. There are a few things that may cause this situation. If the transmission starts to slip, there may be a problem in the hydraulic part of the system like...

Replaced the fuel pump and still having problems starting

If your car will not start, but the fuel pump is new, then it is likely a problem with something else; perhaps the ignition, or induction system. As this type of condition is sometimes difficult to diagnose, I would recommend...

Related articles

P0065 OBD-II Trouble Code: Air Assisted Injector Control/Performance
Diagnostic Diagnostic Trouble Code (DTC): P0065 P0065 trouble code definition Air Assisted Injector Control/Performance What the P0065 code means What this code means is that the manifold absolute pressure sensor is not detecting a change in intake manifold vacuum when...
P2447 OBD-II Trouble Code: Secondary Air Injection System Pump Stuck off Bank 2
P2447 P2447 code definition Secondary Air Injection System Pump Stuck off Bank 2 What the P2447 code means P2447 is an OBD-II generic code for the engine control module (ECM) detecting the bank 2 secondary air injection pump stuck in...
P2069 OBD-II Trouble Code: Fuel Level Sensor B Circuit Intermittent
P2069 P2069 code definition Fuel Level Sensor B Circuit Intermittent What the P2069 code means P2069 is an OBD-II generic code for the engine control module (ECM) detecting the fuel level sensor B signal is intermittent. The sensor output voltage...