2019 impreza - P0141 code

[Ozzy]

Hi.
Have 2019 impreza 2.0 DOHC 40k miles and check engine light is on, code P0141 - Bank 1 Sensor 2.
Situation is : same sensor ( OE) was replaced twice in last 2 years, last time in may 2025 and now again. After replacing, rpms still was going up and down till dealer did hard reset. 2 months later same problem again.

No other codes, just P0141

Anybody had same problem?
Thanks

 

[Dick Foster]

All ya gotta do is web search the code and it tells you exactly what the problem is.

It's likely a failed O2 sensor, specifically the pre heater circuit so it could also be wiring or a fuse related to that O2 sensor.
The preheater is used to warm up the sensor so it reads accurately until the sensor gets warmed up to operating temp by exhaust gases.

BTW the only purpose for the second or after CAT sensor is to verify that the catalytic converter is working properly.

The pre cat sensor (sensor 1) is the sensor the ECU uses to determine how to adjust fuel trim.

 

[Ozzy]

I know it is O2 sensor, was changed twice in 2 years. Last time in may, two months ago and still same problem. Each time cost me $700.
I am looking here if someone had similar problem and how i can solve this.

 

[bmart]

Guessing they replaced the wrong one...

 

[Dick Foster]

Like I said the code specifically says o2 2 heater, so it could be a wiring problem. If 12V doesn't get to the sensor, you're gonna get a fault code, no matter how many times you replace the sensor. Just like if you run out of gas, you're not going anywhere regardless of how great the cat runs otherwise.

 

[Ozzy]

Ok. Thank you

 

[Dick Foster]

Get your meter and check the pins of the connector for the affected O2 sensor.
A couple of them need be reading 12V with the ignition in the run position.
That is unless something is amiss which is what's causing the fault code.
Hopefully it's just a fuse or maybe a bad pin in the O2 connector and your search will be at an end.

P0141 - O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)

Don't know what the P0141 code means or how to fix it? We'll break down what this code stands for, the potential causes and symptoms, and how to take care of it yourself.

mechanicbase.com

 

[sixstarsuby]

do note that using anything other than oem anything on subies is useless. oem or it will spit codes.