# Check engine light on 2001 toyota prius **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [December 31, 2008, 6:09pm UTC](https://community.cartalk.com/t/check-engine-light-on-2001-toyota-prius/24160 "2008-12-31T18:09:58Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![axamaxa](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@axamaxa](https://community.cartalk.com/u/axamaxa)\ **Post date:** [December 31, 2008, 6:09pm UTC](https://community.cartalk.com/t/check-engine-light-on-2001-toyota-prius/24160/1 "2008-12-31T18:09:58Z")
Check engine light came on, was diagnosed (at retail auto parts store), as systems weak (spark plug replacement suggested), second diagnosis at independent resulted in O2 sensor: replaced with after-market sensor. Drove 20 miles check engine light came back on. Next time I tried to drive it , it would start but would’t move. Main battery indicator showed severe drain. Towed to dealership. Dealership replaced O2 sensor with Toyota part and replaced a relay (perhaps an ignition relay). Drove a few hundred miles and the check engine light came back on. Independent re-diagnosed as catalytic converter. He reset the computer so that the light went off. Drove 70 miles (meanwhile car passed emissions inspection), drove a few hundred more miles and the check engine light came back on again. So what do I do now? Sell it? Keep on having it diagnosed and repaired? Is it worth it? How much life left in the batteries? ---
**Author:** ![common-sense-answer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/common-sense-answer/32/716_2.png) [@common-sense-answer](https://community.cartalk.com/u/common-sense-answer)\ **Post date:** [December 31, 2008, 6:29pm UTC](https://community.cartalk.com/t/check-engine-light-on-2001-toyota-prius/24160/2 "2008-12-31T18:29:41Z")
How Many Miles Are On This Vehicle ? Other Than This, Is The Car’s Condition Very Good ? ---
**Author:** ![oldschool](https://avatars.discourse-cdn.com/v4/letter/o/e19adc/32.png) [@oldschool](https://community.cartalk.com/u/oldschool)\ **Post date:** [December 31, 2008, 7:00pm UTC](https://community.cartalk.com/t/check-engine-light-on-2001-toyota-prius/24160/3 "2008-12-31T19:00:05Z")
These o2 sensor replacements with repeated “check engine” lights are turning into a very popular topic,I struggle to come up with a check list to handle the situation. Your situation is complicated by the expensive battery situation. ---
**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\ **Post date:** [January 1, 2009, 12:06am UTC](https://community.cartalk.com/t/check-engine-light-on-2001-toyota-prius/24160/4 "2009-01-01T00:06:08Z")
Have it looked at again. It may not be the O2 sensor or cat this time. ---
**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\ **Post date:** [January 1, 2009, 12:46am UTC](https://community.cartalk.com/t/check-engine-light-on-2001-toyota-prius/24160/5 "2009-01-01T00:46:56Z")
Let’s get the real codes not someone’s interpretation. The code should be in the format (P0123) There may be more than one code. ---
**Author:** ![axamaxa](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@axamaxa](https://community.cartalk.com/u/axamaxa)\ **Post date:** [January 1, 2009, 2:08am UTC](https://community.cartalk.com/t/check-engine-light-on-2001-toyota-prius/24160/6 "2009-01-01T02:08:45Z")
89000 miles. Yes, the condition is very good. ---
**Author:** ![axamaxa](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@axamaxa](https://community.cartalk.com/u/axamaxa)\ **Post date:** [January 13, 2009, 6:11pm UTC](https://community.cartalk.com/t/check-engine-light-on-2001-toyota-prius/24160/7 "2009-01-13T18:11:17Z")
a re-test came up with these codes:a)from independent non-certified [P0420]catalytic and b)from ‘Autosome’[P0420] O2 sensor bank 1, and[P3191]fuel air meter auxilliary emission control massive air flow sensor. ---
**Author:** ![axamaxa](https://avatars.discourse-cdn.com/v4/letter/a/9fc29f/32.png) [@axamaxa](https://community.cartalk.com/u/axamaxa)\ **Post date:** [January 13, 2009, 6:13pm UTC](https://community.cartalk.com/t/check-engine-light-on-2001-toyota-prius/24160/8 "2009-01-13T18:13:17Z")
Had it looked at again, and the results appear in the next post below.