There are literally hundreds of reasons for the Check light to come on. You
have to pull codes to find out why the light is coming on now.
The scan tool is not majic, your car is OBD II compliant, this means that
pulling codes is done with a standardized tool that fits all cars. the data
port is located along the bottom edge of the dash board in the general
vicinity of your left leg while you are driving.
> 99 M3 check engine light is coming on regularly. When the car was new
> occasionally vapor lock would cause this... but one readjusted the cap
> and a tank of gas later the light went off. Now it comes on I readjust the
> cap add gas and it goes off then a day later it comes back on.. Gas cap?
> sludge in the tank? sensor wearing out?
this is the check engine light not the check light. They are two distinct
different items
> There are literally hundreds of reasons for the Check light to come on.
> You have to pull codes to find out why the light is coming on now.
[quoted text clipped - 9 lines]
>> the cap add gas and it goes off then a day later it comes back on.. Gas
>> cap? sludge in the tank? sensor wearing out?
John Carrier - 07 Jun 2007 23:04 GMT
> this is the check engine light not the check light. They are two distinct
> different items
Which means something associated with the emissions control is off. It can
be a coil (you'd notice a rough runner), O2 sensor, loose gas cap or a host
of other sensors not quite in spec. Dump the code to find out what needs
what. OBTW, Check Engine usually doesn't effect drivability though some
things (upstream O2 sensor) can effect mileage.
R / John
>> There are literally hundreds of reasons for the Check light to come on.
>> You have to pull codes to find out why the light is coming on now.
[quoted text clipped - 9 lines]
>>> the cap add gas and it goes off then a day later it comes back on.. Gas
>>> cap? sludge in the tank? sensor wearing out?
Jeff Strickland - 07 Jun 2007 23:04 GMT
The light that comes on when the gas cap is not secured is the Check Engine
Light, or Check light for short.
You need to pull codes to see why the light is on.
> this is the check engine light not the check light. They are two distinct
> different items
[quoted text clipped - 11 lines]
>>> the cap add gas and it goes off then a day later it comes back on.. Gas
>>> cap? sludge in the tank? sensor wearing out?