Q: O2 Sensors

asked by on October 14, 2016

I am getting a check engine light. Took to dealer and they said all four O2 sensors came up on diagnostic. They said unlikely that all fail at once reset and told me to drive it. Chk eng light came back on a mile down the road. What should I check?

My car has 170000 miles.
My car has an automatic transmission.

Check Engine Light is on Inspection $79.99 - $89.99 Get a Quote

As you may know the oxygen sensors, which are part of your emissions system, read exhaust gases to determine whether or not the appropriate amount of oxygen is present in the exhaust. Based upon this reading, this information is relayed to the car’s engine control unit (ECU), which then makes a determination as to whether or not to add more or less fuel to the engine. When too much or too little oxygen is present, this will cause check engine light to come on. Too much oxygen may be present in the exhaust gas due to things like an exhaust leak, a vacuum leak, a faulty mass air flow sensor (causing a lean fuel condition) or faulty fuel injectors. Too little oxygen in the exhaust gas may be caused by things like a clogged air filter, a failing mass air flow sensor (causing too much fuel to be introduced to the motor), bad fuel injectors or a clogged catalytic converter. When the O2 sensor is not working properly, this will cause false readings to be relayed to the computer causing inaccurate adjustments to be made to the intake and fuel system in your engine. If you want assistance in diagnosing what is the cause of this symptom, a certified YourMechanic technician can come to your location to perform a Check Engine Light is on Inspection on your vehicle and suggest any repairs.

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

What others are asking

What should I know about rotating my tires?

Proper tire care involves quite a few things. You need to check the tire pressure regularly. You need to inspect the tread for wear. You need to check for damage to the sidewalls. You also need to make sure the...

What do I do if the gas pedal on my truck gets stuck?

In case of an emergency, your truck is equipped with a Brake Over Accelerator feature. This feature allows you to stop the car if the gas pedal gets stuck. To use the Brake Over Accelerator feature. Steadily press the...

Check Engine light, misfiring , and hard to steer

The first thing I would recommend is to have your vehicle scanned for trouble codes with an OBD2 scanner by a qualified technician who will be able to understand the code that is retrieved. If the code does come up...

Air conditioner won't get cool

Hello. The most common cause of the air conditioning coming out hot is the blend door inside the dash, or low refrigerant levels from a leak in the air conditioning system. A qualified mechanic,like one from YourMechanic will be able...

Pressure Control Solenoid 'B' Control Circuit Range/Performance Read more: https://www.autocodes.com/p0965.html

Hello, thank you for writing in. The reason your are not getting a response from your gas pedal is due to the transmission fluid pressure is off, or the computer thinks it is. Typically this is caused by a bad...

I have a 06 Infiniti M45. The service engine light came on. Got the codes of p0420 and p0430. Wondering if I need to replace both O2 sensors.

Hi there. When the codes P0420 and P0430 come up, usually the catalytic converter has failed, but before you determine if you need to replace the catalytic converter, consider checking the following: A damaged or failed oxygen sensor on...

Check Engine Light is on - codes P0313, P0299, P0304

Hi there. Based on what you've described, this could be a combination of faults between 2 or more things; however, I don't believe the coils and spark plugs are at fault. One of the codes is set during a low...

My honda civic 2012 has check DRL system. I am wondering if it will pass emission inspection. I am in Virginia

Hi There, As you may know, the check DRL indication your vehicle is giving you means that the computer is not recognizing some part of the daytime running light function. This is related to the vehicle's automatic daytime light function...

Location of bank 2 sensor 2 f-150 ford pick-up oxygen sensor

The bank 2 sensor 2 is on your right when facing the truck from the front or drivers side. The sensor is in the exhaust after the catalyst. The bank 2 sensor 1 is just below the exhaust manifold before...

Related articles

P0228 OBD-II Trouble Code: Throttle/Pedal Position Sensor/Switch C Circuit High Input
P0228 P0228 code definition Throttle/Pedal Position Sensor/Switch C Circuit High Input What the P0228 code means P0228 is a generic OBD-II code which indicates that the throttle/pedal position sensor/switch C circuit has a high input problem causing the sensor input...
P0144 OBD-II Trouble Code: O2 Sensor Circuit High Voltage (Bank 1, Sensor 3)
P0144 P0144 code definition O2 Sensor Circuit High Voltage (Bank 1 Sensor 3) What the P0144 code means P0144 is the OBD-II generic code which indicates that the Engine Control Module (ECM) has detected excessively high voltage from the bank...
P0690 OBD-II Trouble Code: ECM/PCM Power Relay Sense Circuit High
P0690 means a high voltage problem with the power supply to the ECM/PCM which may cause Check Engine Light to come on or the vehicle will not start.