# 2001 Toyota Corolla - intermittent CEL

**URL:** <https://community.cartalk.com/t/2001-toyota-corolla-intermittent-cel/175277>\
**Category:** Maintenance/Repairs\
**Tags:** corolla, toyota\
**Created:** [February 19, 2021, 1:49am UTC](https://community.cartalk.com/t/2001-toyota-corolla-intermittent-cel/175277 "2021-02-19T01:49:37Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![JenniferH](https://avatars.discourse-cdn.com/v4/letter/j/5fc32e/32.png) [@JenniferH](https://community.cartalk.com/u/JenniferH)\
**Post date:** [February 19, 2021, 1:49am UTC](https://community.cartalk.com/t/2001-toyota-corolla-intermittent-cel/175277/1 "2021-02-19T01:49:38Z")

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Check Engine Light keeps coming off and on; especially after long idles at stop lights. The Mass Airflow sensor was replaced (11/19/19); Oxygen Sensor replaced (11/11/19); Intake Manifold Gasket and Throttle Body Mount Gasket replaced (9/28/2020). It was fine, but has now come back on and off a couple times since then.

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**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\
**Post date:** [February 19, 2021, 10:07am UTC](https://community.cartalk.com/t/2001-toyota-corolla-intermittent-cel/175277/2 "2021-02-19T10:07:31Z")

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Have the codes read and post back and please post the mileage.

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**Author:** ![JenniferH](https://avatars.discourse-cdn.com/v4/letter/j/5fc32e/32.png) [@JenniferH](https://community.cartalk.com/u/JenniferH)\
**Post date:** [April 8, 2021, 4:39am UTC](https://community.cartalk.com/t/2001-toyota-corolla-intermittent-cel/175277/3 "2021-04-08T04:39:16Z")

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Hello,

The code on the 2001 Toyota Corolla was P0171. It has about 144,00 miles.

 ![B2BA3CCE763242DBB0D2EF011FA9704E.png](https://global.discourse-cdn.com/cartalk/original/3X/7/1/7159a975d714a6caee787759490140daf4d4fda6.png)

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**Author:** ![COROLLAGUY1](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/corollaguy1/32/7575_2.png) [@COROLLAGUY1](https://community.cartalk.com/u/COROLLAGUY1)\
**Post date:** [April 8, 2021, 9:11am UTC](https://community.cartalk.com/t/2001-toyota-corolla-intermittent-cel/175277/4 "2021-04-08T09:11:29Z")

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The mass airflow sensor is dirty. Remove it and clean it with carburator cleaner. A dirty air filter is the cause for this part to go bad.Make sure you buy a new air filter and replace it.

[![](https://global.discourse-cdn.com/cartalk/original/3X/8/8/880b73ad11da46a789dac3d0dc49f2b1054f5d0a.jpeg "How to repair fault code P0171 and reset warning light Toyota Corolla VVT-i. Years 2000 to 2019") ](https://www.youtube.com/watch?v=Y8FBGrCT3rM)

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [April 8, 2021, 6:12pm UTC](https://community.cartalk.com/t/2001-toyota-corolla-intermittent-cel/175277/5 "2021-04-08T18:12:54Z")

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Check for any air leaks in the air intake duct.

![image](https://global.discourse-cdn.com/cartalk/original/3X/c/b/cb7a08a599a28c63f2c7c1a0886071ead08a6500.png)

If air leaks into the engine after the MAF sensor, it’ll set that code.

Tester

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**Author:** ![JenniferH](https://avatars.discourse-cdn.com/v4/letter/j/5fc32e/32.png) [@JenniferH](https://community.cartalk.com/u/JenniferH)\
**Post date:** [April 8, 2021, 10:28pm UTC](https://community.cartalk.com/t/2001-toyota-corolla-intermittent-cel/175277/6 "2021-04-08T22:28:39Z")

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Thank you. I will give these things a try!

 ![B2BA3CCE763242DBB0D2EF011FA9704E.png](https://global.discourse-cdn.com/cartalk/original/3X/7/1/7159a975d714a6caee787759490140daf4d4fda6.png)