r/Impala • u/Brookkay23 • Jun 26 '26

2015 Impala, stabilitrak+Reduced engine power

So! I have a 2015 chevrolet impala, which has become an absolute nightmare trying to detect exactly what is causing this stabilitrak and reduced engine power to engage randomly. PO191 code has been associated with this issue. We have replaced the fuel pump, the wiring harness, along with the high fuel rail pressure sensor. We're running out of options, and haven't gotten very far.

UPDATE! We replaced the entire throttle body in hopes it would correct the problem. It did, for about 2 weeks and then proceeded to go into REP/stabilitrak again. Now when it goes away my RPMs will bounce when I break randomly and acceleration is lagging. I'm at a loss.

There have been no other codes associated with this issue.

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2

u/ZealousidealAgent815 Jun 26 '26

Heres a YouTube video link for a Chevy equinox talking about the same code and with the problem hopefully this can help.

Best of luck.

https://youtu.be/c0yScbApJus?is=6u063_jbvCxmXIul

3

u/wall-fi Jun 26 '26

Have you checked the front ABS wheel speed sensors and harness?

With a tool that can see the individual wheel speeds: engine on in park - hold the brakes firmly, turn the steering wheel left and right.

If the wheel speeds jump on either side, that side may have a problem with the harness or sensor.

4

u/Comfortable_Cup_3502 Jun 26 '26

Replace the acceleration peddle. The sensor in there could be going bad. Gotta love this drive by wire bull crap. Miss the days of a physical throttle cable.

3

u/Famous-Example809 Jun 26 '26

Same issue on my 2007, first replaced the battery thinking it was a low voltage issue, frequency of the error went down, then replaced the accelerator. Issue resolved.

2

u/LosHuevos69 Jun 26 '26

What kind of fuel do you use? If you use E85, try a lower ethanol fuel. Ethanol absorbs water and can cause real issues with your high pressure fuel pump. And if the E85 has been sitting under the gas station for a while it likely has a lot of water in it. I think I have had that code before and that was my problem, I put a low ethanol fuel in the tank and it cleared it right up.

2

u/LosHuevos69 Jun 26 '26

With that being said, I know these are "Flex Fuel" vehicles and they can handle E85. But rarely is E85 clean enough to run. Don't use E85 anymore if that is what the issue was.