check engine light wont go off?

Question

I HAVE A 1996 FORD EXPLORER, I HAD THE AUTO ZONE COMPUTER THING AND IT SAID I NEEDED A OXYGEN SENSOR SO I BOUGHT ONE, HAD IT PUT ON AND THE CHECK ENGINE LIGHT IS STILL ON. NOW WHAT. I NEED TO GET INSPECTED BUT CANT WITH THAT LIGHT AND WHEN I RESET IT, THE LIGHT WENT OFF FOR ABOUT 2 HOURS AND CAME BACK ON WHAT DO I DO NOW?

Answer 1

Hey I agree with robert h usually there's up to three 02 sensors. 1 or 2 up stream (ahead) of the converter called pre-cat 02 sensors and 1 usually after or post cat 02 sensor.They did the same thing to me on my dodge and it was actually the post-cat 02 not the pre-cat 02 that they told me.And unplugging the light is not going to work. OBDII stores DTC's (diagnostic trouble codes) which turn on MIL (malfunction indicator lamp) check engine,etc., in the computer.If you disconnect the neg. battery terminal and turn the key to start and hold it(neg. still disconnected) for 5-6 seconds it might clear it, but if you go for emissions test shortly after it will show a tamper error in the system.Automatic failure.Basically not enough start up cycles/miles for the system to re-learn.See if they were using a code/reader or a scanner at autozone.If they use a scanner it should give 02 readings.I believe Milli amps the pre-cat 02's voltage jumps around alot .200/.900 were the post cat seem to be alot slower and not much fluctuation in voltage stay more on the high side.900/.700 I'd lean toward a post cat 02.(u didn't say which one u changed) See if they pull another code(It's free).good luck

Answer 2

If the your car has gone to 3 different shops and their code reader detected a fault with the same code and has been replaced with a new one then the problem may lye in the a faulty wire to or from the main computer. Depending on the code reader they were using may not have the capability to perform a function that will reset adaptation or monitor the suspected part. Some late model cars have the capability of flashing the prom chip in the computer that fixes any known bugs in the chip. I suggest taking the car to the GMC dealer because they have the proper test equipment to monitor and performed specific activation test to isolate the problem. Your chances of them finding the culprit is much likely than a shop that doesn't have the proper equipment. If they do pinpoint the problem in a timely fashion they will call u give an accurate estimate to repair it. And that's when u decide if it's not worth fixing. But give them a try. It beats financing a new car and keeping the extra funds for more important things. Good luck!

Answer 3

You got screwed. There is no OBD II code for "Bad Oxygen Sensor, Replace." The codes only tell you the symptom. They do not tell you what to replace. There are codes that indicate an Oxygen sensor is not functioning properly, but that does not mean the sensor is bad. The problem can be (and usually is) caused by something else. Since you replaced the O2 sensor and the problem returned then we can be fairly sure the O2 sensor was not the real problem.

You need to go to a real shop with real diagnostic equipment and expertise to have a real diagnostic done to find and fix the problem.

Answer 4

The light is on because some reading reaching the computer is not within normal ranges, and the light is telling you the vehicle needs attention. Auto Zone is in business to sell parts, not diagnose vehicle problems. You are correct that the check engine light being on equals an automatic fail in the inspection. Avoid Auto Zone this time, and take it to a competent mechanic who can read the trouble codes and fix whatever the problem is so you can be inspected.

Oh, and please don't type in all caps, it's hard to read, and is the cyber equivalent of shouting, which makes it rude also.

Answer 5

There are a number of sensors on your Explorer. Such as;
due to emission controls, you may not have tighten the gas cap or sometimes a sensor can get wet & set off the warning light or low oil or ....?
Since you already paid Auto Zone, see if they can help. In the future, you would be better off going to a good Ford dealer.

Answer 6

I had the same problem with an 88 Camaro. It came up as an EVAC code, which is anything to do with emissions. Sometimes, replacing the gas cap will solve the problem but, after the computer is reset, if it comes back on, it's a matter of troubleshooting, as it could be something as small as a pinhole in a hose. You might be able to clear the computer long enough to get it to pass the test. Good luck.

Answer 7

There are other things that can cause that indicator to light up. A Ford dealer can tell you the correct repair(s) for that issue.
The OBDC readouts that you get at the chain stores are not always accurate since they have to deal with any make of vehicle.

Answer 8

Those lights half A S S work. I have a 2002 Dodge Neon and the light comes on every once in a while and goes off by itself. The car runs fine. Don't trust those dumb lights. My father has a 2004 car and his does the same thing. They are so touchy. If youi car is running fine don't worry about it.

Answer 9

make sure you replaced the right sensor(might be 3 of them)when you replace an O2 sensor the ecm has to cycle (3-7 days). even if you turn the code off it's possible to set off again or there might be another code. have it read again.

Answer 10

I would take the car back to the garage and have the mechanic run the diagnostic again. A failure code on the OBDII shold tell you what's going on. Let them keep the car for a while and run it to see if the light comes on again.