# 2004 Toyota Sienna - check engine light **URL:** \ **Category:** General Discussion\ **Created:** [January 13, 2015, 3:56am UTC](https://community.cartalk.com/t/2004-toyota-sienna-check-engine-light/88664 "2015-01-13T03:56:49Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![RodK](https://avatars.discourse-cdn.com/v4/letter/r/c6cbf5/32.png) [@RodK](https://community.cartalk.com/u/RodK)\ **Post date:** [January 13, 2015, 3:56am UTC](https://community.cartalk.com/t/2004-toyota-sienna-check-engine-light/88664/1 "2015-01-13T03:56:49Z")
The check engine light on my 2004 Toyota Sienna is on. Vehicle has about 140000 miles. A check by AutoZone found that the code was P0430 = Bank 2Cat Conv. What things could cause this code - bad cat conv, bad O2 sensor or something else? ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [January 13, 2015, 9:28am UTC](https://community.cartalk.com/t/2004-toyota-sienna-check-engine-light/88664/2 "2015-01-13T09:28:57Z")
Bad cat converter or bad O2 sensor. 10 years and 140K is right in the “normal” lifespan of Toyota converters. Save your pennies and find a reputable independent repair shop. You’ll save hundreds over a dealer. ---
**Author:** ![SteveC76](https://avatars.discourse-cdn.com/v4/letter/s/958977/32.png) [@SteveC76](https://community.cartalk.com/u/SteveC76)\ **Post date:** [January 13, 2015, 9:36am UTC](https://community.cartalk.com/t/2004-toyota-sienna-check-engine-light/88664/3 "2015-01-13T09:36:56Z")
On the sienna with the mileage you have I would almost guarantee the cat is belly up. Find a shop with a scan tool and have them check the performance of the O2 sensors and go from there. ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [January 13, 2015, 9:39am UTC](https://community.cartalk.com/t/2004-toyota-sienna-check-engine-light/88664/4 "2015-01-13T09:39:01Z")
If you google “Toyota P0430” or something similar, you should get some info on what things could cause this code to appear. Experienced Toyota mechanics would have a checklist of tests to do to decide what was actually wrong. If that’s the only code though, no codes for engine misses in particular, I concur w/TSM above, it is likely simply that you need a replacement cat. Before replacing the cat though, make sure all the routine maintenance suggested in the owner’s manual is up to date. You don’t want some other problem to cause a rich mixture and foul up the new cat too. ---
**Author:** ![JoeMario](https://avatars.discourse-cdn.com/v4/letter/j/3bc359/32.png) [@JoeMario](https://community.cartalk.com/u/JoeMario)\ **Post date:** [January 13, 2015, 4:13pm UTC](https://community.cartalk.com/t/2004-toyota-sienna-check-engine-light/88664/5 "2015-01-13T16:13:50Z")
I agree there’s a reasonable chance the cat is gone, but as others have noted, it’s definitely worth having the O2 sensor checked first.