# Persistent P0140 Code - Buick 3.8

**URL:** <https://community.cartalk.com/t/persistent-p0140-code-buick-3-8/153282>\
**Category:** Maintenance/Repairs\
**Created:** [November 21, 2019, 6:12pm UTC](https://community.cartalk.com/t/persistent-p0140-code-buick-3-8/153282 "2019-11-21T18:12:22Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![marktwark](https://avatars.discourse-cdn.com/v4/letter/m/e95f7d/32.png) [@marktwark](https://community.cartalk.com/u/marktwark)\
**Post date:** [November 21, 2019, 6:12pm UTC](https://community.cartalk.com/t/persistent-p0140-code-buick-3-8/153282/1 "2019-11-21T18:12:22Z")

</div>

The P0140 code persists after I have replaced the O2 sensor and EGR valve on my 1996 Park Avenue (115K). The engine, however, runs flawlessly. Besides any suggestions to remedy this problem, is it advisable to take a road trip and ignore the problem?

---

<div class="post-metadata">

**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:** [November 21, 2019, 6:19pm UTC](https://community.cartalk.com/t/persistent-p0140-code-buick-3-8/153282/2 "2019-11-21T18:19:33Z")

</div>

Did you replace the O2 sensor after the catalytic converter?

Tester

---

<div class="post-metadata">

**Author:** ![marktwark](https://avatars.discourse-cdn.com/v4/letter/m/e95f7d/32.png) [@marktwark](https://community.cartalk.com/u/marktwark)\
**Post date:** [November 21, 2019, 6:25pm UTC](https://community.cartalk.com/t/persistent-p0140-code-buick-3-8/153282/3 "2019-11-21T18:25:53Z")

</div>

Hmm, I actually didn’t know there was one after the converter. I replaced the sensor just in back of the engine.

---

<div class="post-metadata">

**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:** [November 21, 2019, 6:29pm UTC](https://community.cartalk.com/t/persistent-p0140-code-buick-3-8/153282/4 "2019-11-21T18:29:07Z")

</div>

The code is for the O2 sensor after the converter.

Tester

---

<div class="post-metadata">

**Author:** ![marktwark](https://avatars.discourse-cdn.com/v4/letter/m/e95f7d/32.png) [@marktwark](https://community.cartalk.com/u/marktwark)\
**Post date:** [November 21, 2019, 6:34pm UTC](https://community.cartalk.com/t/persistent-p0140-code-buick-3-8/153282/5 "2019-11-21T18:34:07Z")

</div>

I just went by what the counter guy told me - - lesson learned. I see now that you have responded that there are “upstream” and “downstream” sensors. I’m going out now to try and locate it.

---

<div class="post-metadata">

**Author:** ![marktwark](https://avatars.discourse-cdn.com/v4/letter/m/e95f7d/32.png) [@marktwark](https://community.cartalk.com/u/marktwark)\
**Post date:** [November 21, 2019, 8:16pm UTC](https://community.cartalk.com/t/persistent-p0140-code-buick-3-8/153282/6 "2019-11-21T20:16:41Z")

</div>

Sensor found and replaced. Code removed. We’ll see what tomorrow brings. Many thanks.

---

<div class="post-metadata">

**Author:** ![marktwark](https://avatars.discourse-cdn.com/v4/letter/m/e95f7d/32.png) [@marktwark](https://community.cartalk.com/u/marktwark)\
**Post date:** [November 22, 2019, 10:27pm UTC](https://community.cartalk.com/t/persistent-p0140-code-buick-3-8/153282/7 "2019-11-22T22:27:59Z")

</div>

Success. Much appreciated!