Idiot ("Check Engine") light won't go away ...

[Surendar Jeyadev]

Sometime back (around 45K miles) the "check engine" idiot light
started to come on in my Subaru 2000 Legacy. It has stayed on for
periods as long as a month, before magically disappearing .... and
appearing again. Sometimes, when the light is on, the car starts
very roughly, but a couple of minutes of idling (at best, usually
about 30 s will do) will make the engine settle down.

I took the car in last week for the 60 K mile service and mentioned
this. The light was not on then, but they ran a check, charged me
$74 and said that "no codes were recorded". Sure enough, the next
day, the light came on. It has been on for a week now. What gives?

Any suggestions would be most helpful.

thanks

 

[David]

Sure enough, the next
day, the light came on. It has been on for a week now. What gives?

Any suggestions would be most helpful.

Buy a scanner for $100 and scan the codes and find out. If you're in the
USA, and have a nearby Autozone, they'll probably scan it free. Unless you're
in California.

 

[A7N8X-X]

who offers the scanner?


|
| > Sure enough, the next
| > day, the light came on. It has been on for a week now. What gives?
| >
| > Any suggestions would be most helpful.
|
| Buy a scanner for $100 and scan the codes and find out. If you're in the
| USA, and have a nearby Autozone, they'll probably scan it free. Unless
you're
| in California.
|
|

 

[Ragnar]

So let me get this right. You deliberately let a CEL stay on for the
last 45K miles and now you want answers?

Take it to the dealer the next time the light comes on.

 

[David]

who offers the scanner?

Most auto parts stores. Make sure it's an OBD II scanner. And if you have a 2005
Subaru, make sure it's CAN compatible (many aren't).

Or you can buy fairly sophisticated (and more expensive) ones online for your Palm or Notebook PC.

 

[Mike]

What happens in CA?

Buy a scanner for $100 and scan the codes and find out. If you're in the
USA, and have a nearby Autozone, they'll probably scan it free. Unless
you're
in California.

 

[Edward Hayes]

When you said idiot were you referring to yourself for leaving the
light on for so long or the light only or both?

 

[David]

What happens in CA?

Only certified techs or DIYers can operate scanners here, so Autozone doesn't do
it, and your local garage will probably change you the price of a cheap scanner just to
pull the codes.

 

[John Kearney]

So let me get this right. You deliberately let a CEL stay on for the
last 45K miles and now you want answers?

Take it to the dealer the next time the light comes on.

Got a 02 OBW, had CEL come on intermittently, took it to my local Subie
specialist. Result; undocumented code, to be addressed in next engine
computer update (IE: software fix). Note: nothing wrong with engine.
Alleged s/w fix doesn't address the glitch. CEL continues on/off for
weeks while I dutifully bring it in each time. Meanwhile I experiment
with different fuels. Best results using Shell premium. CEL light stays
off until I switch back to generic mid-grade. Half way (or less) thru
tank, CEL light comes on again.

Bottom line, I don't trust CEL light. It cries wolf too often. Subaru
needs to fix sensors/sensitivity/software. This is a nuisance.

 

[Rhesus Monkey]

I've got an 05 Forester, where is the computer in that car?

 

[lkreh]

This was maybe an overly harsh response, but it's true, they don't call
it an idiot light for nothing. Ignore it at your own risk, and don't
complain when you have trouble down the road. Because of the snowball
effect of engine management problems, it's wise to immediately take you
car to a repair shop when the CEL comes on.

-LK

 

[Jim G]

This was maybe an overly harsh response, but it's true, they don't call
it an idiot light for nothing. Ignore it at your own risk, and don't
complain when you have trouble down the road. Because of the snowball
effect of engine management problems, it's wise to immediately take you
car to a repair shop when the CEL comes on.

-LK

_______________________________________________________________________

CEL (01 OB Wag) on and off for a couple of months, noticed my gas mileage
was suffering. Finally took to the dealer and was told it was my O2 Sensor
and that my plugs were fouled and so was the air filter. I will just assme
the plugs and filter was due to me drving the car too long with a bad
sensor. Got it all fixed ($295) a month ago.

The best part is the CEL light is already doing it's thing again. On for a
couple days, off for a few days, then back on, etc. Gonna cost me another
$50 and who knows how much else.

JG

 

[Mickey]

This was maybe an overly harsh response, but it's true, they don't call
it an idiot light for nothing. Ignore it at your own risk, and don't
complain when you have trouble down the road. Because of the snowball
effect of engine management problems, it's wise to immediately take you
car to a repair shop when the CEL comes on.

-LK

If memory serves me correct, manual says CEL on steady is emissions
issue. Important engine problems results in flashing CEL.

Mickey

 

[Gilles Gour]

If memory serves me correct, manual says CEL on steady is emissions
issue. Important engine problems results in flashing CEL.

Mickey

Coolant temp sensor gives a steady CEL when going bad and this can lead
to an overrich mixture that's bad for the cat and can also leave you
stranded when it fails completely. Happened to me...
No CEL can be taken lightly.

 

[TG]

What gives is your expensive diagnostic system is trying to tell you
something and you are stubbornly ignoring it, not a good move. TG

 

[mulder]

If memory serves me correct, manual says CEL on steady is emissions
issue. Important engine problems results in flashing CEL.

Mickey

On US OBDII cars (96 and newer), a steady CEL means that the ECU has
detected a problem and set a code in memory. The light will remain on
until the problem is not detected again for a certain number of
consecutive drive cycles, but the code will remain in memory for
retrieval. There are literally hundreds of possible codes which is why
it is always pointless to speculate on the reason the CEL is on, the
car must be checked with a scanner to read the code(s). Once the code
info is known proper troubleshooting can be done.
A flashing CEL means only one thing- a real-time misfire. Unlike a
steady CEL which is not urgent, a flashing one must be attended to
ASAP as a sustained misfire can result in catalytic converter
overheating and damage.

 

[John O]

If memory serves me correct, manual says CEL on steady is emissions

On US OBDII cars (96 and newer), a steady CEL means that the ECU has
detected a problem and set a code in memory. The light will remain on
until the problem is not detected again for a certain number of
consecutive drive cycles, but the code will remain in memory for
retrieval. There are literally hundreds of possible codes which is why
it is always pointless to speculate on the reason the CEL is on, the
car must be checked with a scanner to read the code(s). Once the code
info is known proper troubleshooting can be done.
A flashing CEL means only one thing- a real-time misfire. Unlike a
steady CEL which is not urgent, a flashing one must be attended to
ASAP as a sustained misfire can result in catalytic converter
overheating and damage.

I was going to post today to note the passing of 100,000 miles on my '99
Outback. But at 100,050 the CEL came on. So much for that celebration. :-(

-John O

 

[Hallan Blaggit]

Well, mine came on for a week, and turned itself off on the way to the
dealership. (And yes, i did the gas cap thing). And no codes were
stored. Then it turned itself on the next day, and went off again two
days later.

My new theory is, why bother? It apparently doesn't mean anything
anyway. You don't need to get snippy with people. Taking it to the
dealer when the light comes on doesn't necessarily accomplish
anything, other than screwing up a day's work.

 

[John O]

Well, mine came on for a week, and turned itself off on the way to the

dealership. (And yes, i did the gas cap thing). And no codes were
stored. Then it turned itself on the next day, and went off again two
days later.

My Mercury Villager is like this. The CEL has been on for at least a couple
years. It's been to three different mechanics, including the dealer, and
there are no codes to be read. They reset it, and the light is back on later
that day. Useful, eh?

-John O

 

[ACW]

For my 2000 Forester with 94K miles the check engine light has been on
for two months. The dealer told me not to be concerned if the light is
steady and the car is running fine. However, if the check engine light
is flashing I was told to have my car towed to the dealer. I did take
the car to a mechanic locally who informed me there was a "funny code"
when he diagnosed the problem. He reset the light. I drove off and
the check engine light came on within a minute. For now I am living
with the light on.

Cheers!

ACW