Auto idle stop completely shutting off car occasionally?

Tiny
JAS0822
  • MEMBER
  • 2009 HONDA CIVIC HYBRID
  • 1.3L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 178,545 MILES
My friend just bought this car, and he went to stop at an intersection and the car did the idle shut off but when he went to release the brake and press gas, it didn’t work. He had to restart the car with the key. He also only has a code for an o2 sensor (B1S2), don’t know if that’s related but let me know. Thanks
Sunday, July 27th, 2025 AT 8:18 PM

8 Replies

Tiny
JAS0822
  • MEMBER
  • 74 POSTS
I guess he doesn’t have the auto idle stop feature from looking at the manual. So, any pointers as to why this is happening would be greatly appreciated.
Was this
answer
helpful?
Yes
No
Sunday, July 27th, 2025 AT 8:28 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

Several different things can cause an engine to stall. For example, an engine vacuum leak, a fuel mixture issue (which could be related to the O2 sensor), fuel pressure, and the list goes on.

Take a look through this link for different possible causes and how to check and repair the issue.

https://www.2carpros.com/articles/stall-at-idle

Let me know if that helps. Also, let me know if the vehicle does this all the time, if it runs normally once moving, or anything other you think may help me narrow this down for you.

Take care,

Joe
Was this
answer
helpful?
Yes
No
Sunday, July 27th, 2025 AT 8:41 PM
Tiny
JAS0822
  • MEMBER
  • 74 POSTS
So he’s only had the car since Thursday, and it happened once on Saturday and once today. Everything fuel-wise seems to be working good. I just didn’t know if a downstream o2 sensor could cause that.
Was this
answer
helpful?
Yes
No
Sunday, July 27th, 2025 AT 8:51 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Nope, a downstream oxygen sensor will not cause the engine to stall. I would service the throttle body and then use a smoke machine to test for leaks. Here is a guide and video to show you how.

https://www.2carpros.com/articles/throttle-actuator-service

and

https://www.youtube.com/watch?v=LRKWV4Are5c&t

Here is how to service the throttle body on your car. Check out the images (below). Please let us know what happens.
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Tuesday, July 29th, 2025 AT 11:00 AM
Tiny
JAS0822
  • MEMBER
  • 74 POSTS
Okay unrelated to the original but we replaced the o2 today and the original code went away but a couple hours later a new code popped up saying “System too lean Bank 1” P0171.
The cars not running sluggish, all the fuel is working right, the air filter and the mass airflow is brand new. There’s no vacuum leaks that I can hear and I don’t see any cracking. Any ideas on what could be throwing that code?
Was this
answer
helpful?
Yes
No
Tuesday, July 29th, 2025 AT 9:02 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yep, that is a lean code, This is most likely cause by a bad MAF sensor which is common. Here is a guide to go over and the location of the sensor, clear the codes once the job is completed.

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

Check out the images (below). Let us know how it goes
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Wednesday, July 30th, 2025 AT 9:34 AM
Tiny
JAS0822
  • MEMBER
  • 74 POSTS
The mass airflow sensor is brand new
Was this
answer
helpful?
Yes
No
Wednesday, July 30th, 2025 AT 9:42 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
My bad, yep, it sounds like there is an intake leak, here is a video to check.

https://www.youtube.com/watch?v=LRKWV4Are5c&t

Let us know how it goes
Was this
answer
helpful?
Yes
No
Wednesday, July 30th, 2025 AT 10:56 AM

Please login or register to post a reply.

Related Engine Stall While Driving Content

Code Read Retrieval/Clear Honda
VIDEO
Code Read Retrieval/Clear Honda
Instructional repair video
Engine Stalls While Driving
GUIDE
Engine Stalls While Driving
An engine that stalls while driving and then starts back up again, either immediately or after a short time is different from an engine that just wont start or if the...
VIEW MORE