# OBD codes on 2003 Malibu **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [January 13, 2015, 8:00pm UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673 "2015-01-13T20:00:42Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![taylorlucy2](https://avatars.discourse-cdn.com/v4/letter/t/f04885/32.png) [@taylorlucy2](https://community.cartalk.com/u/taylorlucy2)\ **Post date:** [January 13, 2015, 8:00pm UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/1 "2015-01-13T20:00:42Z")
I have a 2003 malibu with 170000 miles on it. My husband uses this car to commute to work (10 miles one way). We will be buying a newer car in a month or so but my husband really wants to keep this car as a third/back up car. I purchased an OBD 2 scanner and downloaded the torque app (I really enjoy working on cars and I wanted to have more info easily available to me). The codes that it is showing me are P0131 (o2 sensor) and P0405 (EGR?). How should I proceed? I know I need to replace the O2 (easy) but im not sure about the other code. The car has a rough idle, terrible gas mileage, and seems to drive as though I have shifted it past Drive and into 1st (its an automatic). ---
**Author:** ![insightful](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/insightful/32/2732_2.png) [@insightful](https://community.cartalk.com/u/insightful)\ **Post date:** [January 13, 2015, 10:58pm UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/2 "2015-01-13T22:58:49Z")
“…seems to drive as though I have shifted it past Drive and into 1st (its an automatic).” Are you saying it literally seems to be stuck in 1st, i.e., the engine revs high on the tach? ---
**Author:** ![taylorlucy2](https://avatars.discourse-cdn.com/v4/letter/t/f04885/32.png) [@taylorlucy2](https://community.cartalk.com/u/taylorlucy2)\ **Post date:** [January 14, 2015, 3:27am UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/3 "2015-01-14T03:27:55Z")
Yes, pretty much how you phrased it. It revs high. The car says its in drive but it doesnt feel like it when its driven. It will get up to high speeds (its driven at around 60 mph a few days a week) but it seems like the engine is working harder than it should. Im not sure how else to describe it. I hope this helps. ---
**Author:** ![knfenimore](https://avatars.discourse-cdn.com/v4/letter/k/9fc348/32.png) [@knfenimore](https://community.cartalk.com/u/knfenimore)\ **Post date:** [January 14, 2015, 3:37am UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/4 "2015-01-14T03:37:36Z")
O2 will cause the fuel mixture to be wrong. an EGR valve that’s stuck open will cause a noticeable drop in horsepower at the very least. Along with that may come detonation – “knock” or “ping” – under hard acceleration, and the attendant cylinder misfires. The engine will also see an open EGR valve as a massive vacuum leak, so expect hard starting and a very rough idle. An EGR stuck closed or clogged with carbon won’t exhibit many symptoms, since engines don’t technically need them to run. But expect a very noticeable drop in fuel economy, a noticeable gasoline smell from the exhaust pipe, a very hot catalytic converter, or all of the above. ---
**Author:** ![taylorlucy2](https://avatars.discourse-cdn.com/v4/letter/t/f04885/32.png) [@taylorlucy2](https://community.cartalk.com/u/taylorlucy2)\ **Post date:** [January 14, 2015, 4:13am UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/5 "2015-01-14T04:13:05Z")
I don’t have any hard starting or rough idling. Even in below zero temperatures, it has always started right up and runs fairly quietly until its time to move. My OBD scanner hasnt detected any misfires (which kind of surprised me). And I also dont have any “knocks” or “pings”. Just hard acceleration, meaning it seems like its working harder to accelerate than it should. ---
**Author:** ![insightful](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/insightful/32/2732_2.png) [@insightful](https://community.cartalk.com/u/insightful)\ **Post date:** [January 14, 2015, 4:50am UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/6 "2015-01-14T04:50:57Z")
This guy finally changed his EGR valve: Have you done a transmission fluid and filter change lately? ---
**Author:** ![taylorlucy2](https://avatars.discourse-cdn.com/v4/letter/t/f04885/32.png) [@taylorlucy2](https://community.cartalk.com/u/taylorlucy2)\ **Post date:** [January 14, 2015, 11:02am UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/7 "2015-01-14T11:02:20Z")
Actually no I haven’t. Could that be one of the issues? ---
**Author:** ![taylorlucy2](https://avatars.discourse-cdn.com/v4/letter/t/f04885/32.png) [@taylorlucy2](https://community.cartalk.com/u/taylorlucy2)\ **Post date:** [January 14, 2015, 1:33pm UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/8 "2015-01-14T13:33:03Z")
Could it really be the cat converter? ---
**Author:** ![insightful](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/insightful/32/2732_2.png) [@insightful](https://community.cartalk.com/u/insightful)\ **Post date:** [January 15, 2015, 1:07am UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/9 "2015-01-15T01:07:06Z")
Beginning to sound like several problems. How badly do you really want to keep this car? ---
**Author:** ![taylorlucy2](https://avatars.discourse-cdn.com/v4/letter/t/f04885/32.png) [@taylorlucy2](https://community.cartalk.com/u/taylorlucy2)\ **Post date:** [January 15, 2015, 4:13am UTC](https://community.cartalk.com/t/obd-codes-on-2003-malibu/88673/10 "2015-01-15T04:13:07Z")
I don’t want to keep this car. Lol. My husband is the one who wants to keep it. Just as a third/emergency car.