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EVAP system code 0449

12-03-2007, 09:27 AM

Hello, everyone:

I am new to this forum and I need you help.

The car is a 2002 Buick LeSabre,custom, 4dr, AT, 19000mile.

I did not have a chance to use this car for three months during hot summer, then the battery was totally dead. Bought a new battery. The car then starts, runs normally except both " service engine soon" and "ABS" lights won't go off. Drove to a mechanic. He tried to delete the light and they keep coming back. So he looked at the error code and found out it was 0449. He said this is because gas pipline problem and needs lot of time and money to fix it.

Car never had any problem before. How could it suddenly has such big problem when just replacing a battery?

Is his diagnosis right? how to fix it? Thanks a lot

12-03-2007, 11:29 AM
Welcome to AF, this code refers to a problem in evap system, the abs is a seperate issue and needs to be scanned with an abs function scanner. There is no way for us to tell why and how this came about, nor can we challenge his diagnosis without on site analysis.

12-03-2007, 11:55 AM
Thanks, Maxwedge. Is there any fix for the evap system then?

12-03-2007, 01:12 PM
Hi, All
I did internet research and found out that malfunction code o449 is: EVAP VENT sol control circuit. problem with this code is the service engine soon (bottom one) stays on even though starting, running, and driving the car is not a problem at all (I posted a thread earlier). Any suggestion as where the circuit is and how to fix it will be greatly appreciated. Thanks.

(car file: 2002 buick, leSabre, custom, AT, 4dr)


12-03-2007, 03:19 PM
The code is actually P0449 and like you found, is a code for the Evap solenoid control circuit. You could just have a loose or broken wire or connector. When the battery was replaced, was the ground cable removed first?

auto trainy
12-05-2007, 06:49 PM
Hot Z I read a lot lately about disconnecting the ground cable first,why.
thank's, Frank

12-05-2007, 07:29 PM
If you remove the positive connector first, in a negative ground system, you risk the chance of creating a spark. That could happen if the wrench you're using to remove the positive terminal connector comes in contact with any piece of metal on the car. If you are working near the battery when this occurs, it might create an ignition source that could cause the battery to explode. Some systems on the car require positive voltage at all times. Even though the current draw is very small, it will still arc. You want this arc on the negative side when connecting the cables to help absorb voltage spikes. Computer controlled cars are very sensitive to voltage spikes, the same as your home computer. The folks who sell & service PCM/ECUs love people who remove the positive cable first & then install the positive cable after the negative cable has been installed! :grinyes:

12-06-2007, 11:53 AM

I was pissed off by several persons this past week. My bad luck. Sorry Could not get back here soon.

As for removing the old battery, I can't remember for sure that I disconnected the negative first, then disconnected positive. But I normally would do in that sequence.

For installing the new one, I probably connected the positive first, then negative second.(stupid, I know)

I also thought of the battery installation because the car had no problem before the battery got dead. How come two problems came up at same time after changing battery?

To correct the possible battery installation mistake, This past Sunday I disconnected the negative for about 30 minutes and then re-connected back on. No touch for the positive. During the action, the negative rod was like a mad dog, whenever I was trying to touch it, sparks coming all over around. Did I made another mistake?

Now, Suppose I did everything wrong when install the battery, Any rescue actions can be performed to solve the P0449 problem? What the right steps to replace the battery. Thanks a lot. (I have to correct it, otherwise i can't pass the emission test!)

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