check engine light turn on????

[mnguyen11111]

hi

Does anyone know specificly why the check engine?
where to check and what to check???

thanks

Mnguyen

[TDLipsey]

Hey. Often times the check engine light will come on due to the gas cap not on properly. I would take the cap off, slowly put it back on tightly, then restart the car three times. The third time the light will go out if it was the cap. If not, take it to AutoZone and have them hook it up to the computer (for free) and have them tell you what code is showing up. It could be a bad sensor, a bad plug, or anything.

Good luck.

[mnguyen11111]

thanks

I am hoping it is the light cap.
I went to auto zone and they said it is the Oxygen Sensor.

thanks again

[dy540i]

Originally posted by mnguyen11111@Aug 4 2004, 12:57 PM
thanks

I am hoping it is the light cap.
I went to auto zone and they said it is the Oxygen Sensor.

thanks again

I had a similar problem, and sure enough it was the $18 gas cap and not the oxygen sensor. When you tighten your gas cap, it should click. If it doesn't, then you'll need to replace it.

[mnguyen11111]

I bought a new O2 sensor
I replace the one that is easy to get to,
but the light still turn on.
when i brought the car to Auto Zone,
he told me the slot 1 is bad.

but i don't know which one is the slot one so i change the easy one.
but now the light is still on after 3 days driving the car.

Please let me know if you have a repair manual that will identify the detail for
O2 sensors on BMW 528i E39

thanks

Nguyen

[325isBaby]

An emissions related fault can keep the check engine light illuminated after the problem has been solved, if the code isn't cleared.

[mnguyen11111]

hi friends,

I decided to change both O2 sensors with a new one.

But do u know if the check engine light will turn off after it is replace or


I have to bring it to the dealer to clear the code?????

thanks

mnguyen

[CosmosBlack]

How many miles do you have on your car?
It might not be the O2sensors....they always tell you it is, and it ends up being not!
If you do not have like 80k and up, it's probably not the O2sensors.
And I bet it is not the gas cap either.

[billB]

Cosmos is right.....For O2 sensors think "fine tuning" example? too lean vs. too rich mixture. O2 sensors will TRY to correct but when too much to deal with; O2 sensor becomes overwhelmed. This will trigger another code of "O2 sensors CONTROL LIMIT" again overwhelmed control limit makes one think bad O2 sensors especially the pre cat ones (2 in number) where in fact they are innocent and working so hard to compensate for example to the huge leak somewhere around the intake ...gaskets, vacuum hoses etc etc. a good way to check for those vacuum leaks is to spray break cleaner around the suspected area of leaks or the intake manifold, hoses ; if in fact there is a vacuum leak the intake will suck the break cleaner fluid and the idle will change .Note: for huge leaks you may well hear hissing noise also..etc etc. Once you rule out the leak then we will go for the next step.

regards
Billb