Check engine light wont turn off?

Question

Random misfire in 3rd cylinder, but mechanic says it wont turn off, and nothings wrong. Want to keep this van for 5 more years, is it worth checking into further?

could it have something to do with what they did when I had the distributor replaced?

Answer 1

If you have a random misfire even if you disconnect the battery (negative cable first),the engine code will reset as soon as it happens again .Now as for the misfire first check the ignition cap to see if there are any cracks in it ,if there aren't any proceed to check the rotor to see if maybe one of the contacts are bent, if there ok then check the ignition wires . If all of the above are ok ,then you must take it to a shop and have them put a scan tool on the vehicle. This will tell them if the problem is in the ignition circuit or if the computer is faulty. Now I do not know where you are but in the north east you can go to Auto Zone ,and have them scan your car for codes for free. They will not reset them but at least you can see where the mechanic has to start looking where to fix the problem. Good Luck ,ps-Also check the fuel level if it is lower than a 1/4 tank your fuel pump can be starting to go and this will some times cause a misfire or backfire in the intake manifold.

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

To simply reset the engines computer you can unhook the positive cable from the battery for 30 seconds...that'll turn the check engine light off until the next time it misfires.....you may want to figure out the cause of the misfire...that could lead to backfiring, which will do moderate damage if left unchecked. It could be a timing issue, or something as simple as a plugged or faulty injector....A cheap thing to try is to get a bottle or two of injector cleaner and run through..wether or not it solves the problem it'll only cost you 10 bucks...so worse case scenario you're out ten bucks and still have a misfire.

Answer 4

Ok here is what I would do. Take it to a shop that does engine diagnostics and tell them to keep the van on a scan tool for a couple of hours and see if the van starts to act up and if it does it will say some thing on the scan tool and then you will be able to go from there. Good luck

Answer 5

mechanic is retarded. he probably doesnt know the electronic computer system in your car and he doesnt know how to reset the light. Go to a new mechanic and ask him if he can do it. should take 2 seconds and hopefully they wont charge you.. then again we are talking about mechanics..


PLEASE NOTE: someone below wrote that if you take off your positive terminal for 30 seconds, your computer will reset. When taking off connections from your battery, always take the negative off first and put it back on last. this will save yourself one trip to a funeral. Read your instruction manual before doing this.

Answer 6

Remove the battery for 30 minutes, not seconds, and remove the ground not the positive. The ECUs have a small circuit that provides a backup voltage if power is lost for a few minutes.

If you do this and it comes back on, explore further.

Answer 7

i own a repair shop,and it will turn off,,there has to something tripping it it can be something real simple doing it,,i left my gas cap loose and it tripped mine,,but believe me when a mechanic says it cant be done,,this means he,s went as far as he knows to go with it,,but there's something tripping it ,have someone that is real good at reading a scanner do a check on it,a lot of times it what you don't see or what the scanner don't say that matters,,but it can be turned off and the problem fixed on it,,good luck with it,i hope this help,s.

Answer 8

I can honestly tell you what I would do in this situation if the van is running perfectly. Take out your instrument cluster and take the bulb out of the ck engine light and throw it as far down the street as possible. You will never have a ck engine lt problem again.

Answer 9

oxygen sensor may need to be replaced and then reset switch, if all else if fine.