Rickker

The check engine light came on a few days ago. Today I hooked up the Durametric scan tool and this is what came up:

P0446 - Factory fault code 95
Evap Cannister shut-off valve function (below limit)

I cleared the code, and it has not re-appeared after starting the engine and running it a bit. However, I have not driven the car any distance yet.

Here's the question: Is this something to be concerned about?

Thanks.

...Rickker

fast996

is your gas cap on tight? also have you filled up the gas tank recently, like topped it off?

Rickker

Yes, I filled the tank earlier the same day, then drove about half a tank, and the light came on just as I got home. I'm pretty sure I turned the gas cap for about 3 or 4 clicks after refueling.

redridge

I had this code before, with durametric on..... I checked the gas cap, and it wasnt even on.

fast996

yeah if it didnt come back, topping it off probably filled a vent line causing the code

fast996

well that was easy

logray

You might need a new cap... there are many newer revisions than what comes on a stock 1999 car.

fpena944

Sorry to derail the conversation here but if you were to clear up this code by disconnecting the battery, will the history of the code still be stored and therefore read by the Durametric? Or is it gone forever?

Macster

The code is erased when 12V battery power is removed from the engine controller such as would be the case when the battery was disconnected.

Do *not* ever disconnect the battery with the engine running, the key on, or the key even in the ignition!

Anyhow, the code can not be retrieved once battery power is removed and reapplied (or the code is erased by the use of a code reader/eraser tool).

However, there can be a record of sorts that something was 'cleared'... The engine controller can keep track of how many miles (km actually, though limited to 65535km) the car was driven since the check engine light was cleared (and this may be reset when battery power is removed too). There is another km counter than is used to count the number of km the car has driven since the check engine light came on.

A sophisticated code reader (Durametric should qualify) can read these values if the engine controller supports them. (The are Mode 1 Pids 0x21 and Pid 0x31 IIRC.)

Sincerely,

Macster.

Rickker

FWIW, I drove around for an hour or so today, and the CEL has not come on again. So hopefully, this will be the end of it.

fpena944

Thanks for the explanation. Yeah I've never disconnected the battery when the car is on or the key is in the ignition. But the reason I asked was because I while back I got a MAF code so I cleaned it out and to get rid of the CEL I disconnected the battery.

It never came back but I was wondering if when the time comes that I hook it up to the Durametric, would I still be able to see the history of the codes?

I guess not so at least I know now.

Thanks again!