Last week I got a cel on my 2001 IS300 so i checked what code was coming up and it was P0141 O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2). So this weekend I unplugged connector for that sensor and checked the two heater contacts and it was a open circuit.

So I was wondering does this seem like just a problem with the heater element in the sensor and not the functionality of it? Also will this just cause a bit more fuel consumption until the car heats up or will it actually affect driveability? I'm probably going to replace the sensor soon but will not be able to do it until I can order it and have some more free time.

2/14/2011 9:28:54 AM

http://www.clublexus.com/forums/maintenance/291011-how-to-change-gs300-02-sensor-bank-1-sensor-2-code-p0141.html same engine. Google to the rescue.

it's a rear O2 sensor, behind the cat. It's used to determine whether the cat is working right or not. I'm not sure if it will hurt fuel economy much but I doubt it. A front o2 sensor would have a much bigger effect.

2/14/2011 9:40:02 AM

Since this is a thread about O2 sensors I'll just throw this out there. My '92 Integra GSR still has it's original O2 sensor. I've never had the check engine light come on with that car. But it's 19 years old, can this O2 sensor still be working as it should? lol

2/14/2011 11:21:34 AM

well you're OBD1, so... dont worry about it?

2/14/2011 11:40:37 AM

I don't even know if an OBD I Honda is smart enough to throw an O2 sensor code unless it's unplugged or something.

2/14/2011 1:36:21 PM

^^well yeah it hasn't been inspected for emissions ever since they changed that law in NC.

^Good point. I was just kinda wondering mainly with a thought towards fuel mileage. The car never really tops 30mpg highway anymore. I wonder if it'd be worth it to replace the O2 sensor in hopes of better mileage. The sensor only costs $60.

2/14/2011 1:41:54 PM

Quote :

"I don't even know if an OBD I Honda is smart enough to throw an O2 sensor code unless it's unplugged or something."

Sure it is. If pingpong response time is lazy or if out of range, then yes, it will. My OBD0 Integra ('87) would do it, especially after a lot of abuse on the track.

Patrick...you MIGHT see a little improvement, but also keep in mind that the car relies on speed-density interpolation to ref the fuel/ignition maps and apply trim, and you've got a helluva lotta miles on that car. Accordingly, I'd bet your manifold absolute pressure has risen a tad since the car was new. That right there will cause a decrease in fuel mileage. Of course, on the flip side, that's what the O2 sensor is there for...for feedback and fuel/ignition trim.

2/14/2011 1:50:42 PM