Best Answer

The EGR Valve. HUGE amount of possibilites. There are "monitors" or self tests the computer runs the car through a drive cycle, if a problem occurs, it may not run all of the self tests until that problem is taken care-such as the EVAP monitor. Therefore, another problem may exist. It is emission related. Best bet is to contact the local snap-on dealer and have him refer you to a known good shop that specializes in this technology-he will know. The " check engine light" is by far one of the most misunderstood technological advances by the public. This is an needed in-depth understanding for the public. It is a warning light that is illuminated when there is a problem affecting the EMISSION SYSTEM only. Emission system being the pollution control system. Don't get a hard on against it as it is a good thing once you understand it. One point that was brought up a a recent meeting of technicians was that the amount of hydrocarbons is greater when the gas cap is left off than when the engine is running. Hydrocarbons are part of pollution emitted as gasoline evaporates. Going a step farther, one facet of the emission system is the "Evaporative" portion. This is when the fumes from the gasoline are leaking from the system into the outside air. This is one part of the emission system that can trigger a check engine light. I would say that about 7% of the vehicles that have a check engine light are the result of a loose or inadequate gas cap. But understand that many scenarios are possible with the "check engine light" The vehicle's powertrain computer (note that some vehicles have 17 different computers) will run a series of self-tests. They will only run under certain criteria. And they can be vastly different from manufacturer to manufacturer. Some self-tests are not run until preceding ones have run successfully. So if there is a problem in one particular area that is preventing another self test from running, you can have a situation where one problem is fixed, but another still exists. If you fix a problem and drive the car through a drive cycle that sets the monitor (or self test) the light will go off as it passes that criteria that triggered it in the first place. After 1996, the auto industry went to a idea called OBD II (on board diagnostics). This was to get all the manufacturers onto a similar plane for troubleshooting and powertrain control. While they still differ vastly, many corrections and adaptations were made for technicians to better fix the check engine light problems. Prior to this there were so many different and poor troubleshooting data from a check engine light problem that resolving the problem was much more difficult. Many early warning light of this nature were set to illuminate based on mileage. An Oxygen sensor was one of the things that were meant to be replaced when that mileage was hit. This is much like many current "Change oil lights

User Avatar

Wiki User

โˆ™ 2005-11-02 02:34:17
This answer is:
User Avatar
Study guides

Create a Study Guide

Add your answer:

Earn +20 pts
Q: Your engine check light has come on twice in the last year one time it was a oxygen sensor now what can it be?
Write your answer...
Related questions

Should the check engine light come on if an O2 sensor is bad?

The oxygen sensor is one of many things that could turn the check engine light on.The oxygen sensor is one of many things that could turn the check engine light on.

Does the oxygen sensor make the check engine light come on?


How do you know an oxygen sensor is bad?

the check engine light will come on

What does it mean when your check engine light comes on it reads heated oxygen sensor bank?

There is a failure in the oxygen sensor heater.

Will an bad oxygen sensor make the engine check light come on?


Would the check engine light come on if the oxygen two sensor needed replacement?

The O2 sensor is one of many things that can turn on the check engine light. You need to have it checked for codes.

What happens to a 1999 Honda Accord when the oxygen sensor goes bad?

When the oxygen sensor goes bad, the check engine light goes on.

Check engine 2001 Isuzu Rodeo?

The check engine light for the 2001 Isuzu Rodeo often comes on because of a sensor that is damaged or malfunctioning. The most common sensor is an oxygen sensor and when reset, this often allows the light to be reset.

What happens if the oxygen sensor goes bad?

The check engine light will illuminate. The code(s) will direct you to the faulty sensor.

How do you check the oxygen sensor on 97 Dodge 318?

Oxygen sensors either work or they don't. If they don't, the check engine light will come on and indicate an oxygen sensor problem. If they're fine, none of that will happen.

What does it indicate when check engine light is on on a 2000 Volvo s 80?

the oxygen sensor(sensors)

2000 Chevy cavalier check engine light on?

could be the oxygen sensor. that's what it was on mine.

If the oxygen sensor behind the catalytic converter is bad will the check engine light come on?


What are Signs of a bad oxygen sensor jeep wrangler?

Check engine light would appear.

What happend when oxygen sensor go bad on 1996 impala?

The check engine light will illuminate.

How do turn off check engine light on 1998 Toyota Sienna?

must be a oxygen sensor

Can the oxygen sensor cause the car not to start?

no it can't. usually when the oxygen sensors are failing, u get your check engine light on.

How do you fix an oxygen sensor?

Unfortunately there is no fixing an O2 sensor. If the "check engine" light is on due to an O2 sensor, it can only be remedied by replacing the bad sensor.

What are the signs that an oxygen sensor needs to be changed?

The check engine light will illuminate with a code(s) directing which O2 sensor is bad.

2000 Honda civic check engine light?

Check the OXYGEN SENSOR Do it yourself: $70.00 Professional: $220.00 Difficulty: Beginner

Will my check engine light turn off automatically when you replace the oxygen sensor?

It will after a drive cycle, if that was the original problem.

How do you know if the oxygen sensor on a 1995 Chevy S10 4x4 is bad?

The check engine light would come on.

Why would the cam sensor turn on check engine light?

That is what the check engine light is for. It informs you of a failure.

How do you know when the oxygen sensors need changing?

If the o2 sensor is not working, the computer will put out a code which will turn on your Check Engine light. The car/truck will not pass inspection without it being fixed. Anytime the check engine light is on, the mechanic will plug into the vehicle's computer and it will tell him the fault codes and what they mean so that he can fix them. So, if the check/service engine light is off, the oxygen sensor should be fine.

Where do you locate the check engine light sensor for 1997 Cheyenne 1500 truck?

There is not one sensor. All the ECM sensors are tied to the check engine light.