Reset ECM after oxygen sensor replacement

Tiny
SPIKEDWHEELS
  • MEMBER
  • 2015 CADILLAC ATS
  • 2.0L
  • 4 CYL
  • TURBO
  • 4WD
  • AUTOMATIC
  • 90,000 MILES
I recently did a maintenance on the car and replaced the upstream oxygen sensor. How can I reset the ECM so I can trigger the learning procedure for the idle air control? The rpm is all over the place at idle. Disconnecting the battery and reconnecting doesnt seem to work
Monday, April 25th, 2022 AT 4:48 PM

7 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Couple questions. First is the check engine light on? If it is on, then we need to check for codes.

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Just clearing the codes will not solve any issue that is causing the light to turn on.

As for resetting the ECM, that is unlikely to fix the issue even if it relearns the throttle.

However, I am attaching the throttle relearn process below for you to try just in case I am missing something.

Please run through this and let us know what questions you have.

Thanks
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Tuesday, April 26th, 2022 AT 8:00 AM
Tiny
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Thank you for this.
I had a P015B code and was told to replace the oxygen sensor. I have a Bluetooth OBD scanner and it shows the code is Permanent. The procedure you shared I guess require an actual scan tool?
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Tuesday, April 26th, 2022 AT 10:14 AM
Tiny
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In order to get the throttle to relearn you will need to clear all the codes. So, in order to clear this code, we will have to find out why it is still active/permanent.

Basically, this is telling us that the o2 sensor is not reading the correct or desired oxygen content. So, we need to find out if we have anything that would cause this issue and if not, we need to replace the sensor.

I see you replaced the upstream o2 sensor, so we need to check out the rest of this info.

Also, this may also point to the issue that is causing the idle issue. This may be a vacuum leak so here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know if you have questions. Thanks
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Tuesday, April 26th, 2022 AT 11:22 AM
Tiny
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Before the change I didn't get any rough idle. I'm thinking cause it's an NGK sensor and not AC Delco. Looking online in reading that GM computer doesn't like aftermarket O2 Sensor. I still have the old one, maybe I'll change it back and see if it fixes the issue. I'll also look for a vacuum leak. Any ideas how to pinpoint a vacuum leak?
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Tuesday, April 26th, 2022 AT 1:48 PM
Tiny
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Okay. Just to be clear, you had no issue prior to changing just the o2 sensor and now you have this issue? If that is the case then yes, I agree that the ECM doesn't like the readings it is getting from this sensor, and I would change it again and go with an OEM just to be safe.
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Tuesday, April 26th, 2022 AT 1:58 PM
Tiny
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I had P015B on. I live in a far northern remote community (think arctic North) and I'm trying to fix and diagnose this myself due to lack car mechanic. Now I'm getting a P0132 all of a sudden. Going to switch the old one back and try to see if I can find a vacuum leak. Thanks for your advice. I'll keep you posted.
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Tuesday, April 26th, 2022 AT 2:37 PM
Tiny
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Sounds good. That code is telling you that the ECM is seeing that the heated o2 sensor is shorted to ground so I would suggest when you swap it back that you inspect the connector really well and look for corrosion or anything green growing on the metal pins. This would explain why you are getting these codes.

However, if this is not the issue then we are going to have to get a new post started to dig into this o2 sensor issue.

Basically this post started as an ECM reset and we have moved into an o2 sensor issue and others will not find the solution to an o2 sensor issue that they may have under this topic. We are not not only here to help you but when you solve this, you will help others when they read this.
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Wednesday, April 27th, 2022 AT 9:40 AM

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