Check Engine Lights:
There seems to be a lot of confusion as to what to do
when the check engine light in your Subaru
comes on. The check engine light, often referred to in literature as the MIL for "malfunction indicator
light", comes on when there is something going on with the vehicle that would keep it from passing
an emission test. As a matter of fact, it is actually the computer in your car that does the
emissions test. When you go for your state test the test facility plugs their computer into
yours to confirm that all of the systems that are tested have indeed been tested and that the
computer has not been tampered with.
There are many things that will cause the check engine light to come on but it doesn't exactly
mean that there is something wrong with the engine. For instance, running the engine low on oil
does not turn the check engine light on until the low oil level causes some other malfunction
such as a valve timing solenoid (that is operated by oil pressure) to malfunction. Letting the
engine oil level get this low is very bad for the engine and is either an indication that it has
been too long between oil changes or there is an issue, such as a leak, causing the engine to use
When the check engine light does come on the cruise control light will blink indicating that the
cruise control has been disabled and the vehicle's dynamic stability control light will come on
indicating that it also has been disabled. There is no reason to panic and it is okay to keep
driving the car.
Many of the things that turn the check engine light on cause no drivability issues at all, the
check engine light is the only indication there is a problem. Some of the things that turn the
check engine light, such as a knock sensor or Oxygen sensor, may cause subtle drivability issues
and certainly will affect fuel mileage. The bottom line is that in these situations, although it
is okay to drive the car, the check engine light should not be ignored.
If the check engine light is flashing it means that one or more of the engine's cylinders are
misfiring. It should be obvious to the operator that something is wrong with the car and when
this is happening the car should not be driven any further than necessary or damage to the
catalytic converter will occur.
Intermittent misfire codes can be one of the most difficult diagnostic challenges to solve. The
first lesson in auto-engine 101 is that an engine needs properly synchronized fuel, spark and
compression to run. The misfire occurs when one or more of these three things don't happen
when it is supposed to.