Thread: P0171 after installing headers

Thanks Tony, I'll give that a try and let you know what I come up with.

Well, the connector was sending it the correct voltages, however, the current to/from the circuit was much lower than expected. When I pulled the sensor out, it was covered in black soot. I cleaned the soot off with some carb cleaner, and after re installing the sensor, I got a p0134 code. "Sensor no activity". Ideas?

Did you plug it back in?

Originally Posted by dsmuts

Did you plug it back in?

Of course, it's still currently plugged in. I also checked the #21 fuse under the hood, looks perfectly fine, swapped it with another 15A fuse just in case. Still the same problem.

Run the wiring and look for any bare spots. Might have to end up replacing the sensor.

You killed the sensor. I know some have cleaned O2 sensors and have had luck but those are few and far between. There is really no effective way to clean the sensor. I could go into alot of technical mumbo jumbo on O2 sensors but I'll keep it simple: Ya killed it if the circuits and connections are good.

The black soot on the sensor....I would be curious as to why that is. Check into that as its not normal. Keep us posted

Black means rich. Can be normal if he's been running it for short periods trying to fix something.

Originally Posted by dsmuts

Run the wiring and look for any bare spots. Might have to end up replacing the sensor.

This is what I'm thinking. This dumb thing has given me 3 different codes since moving it into my headers. I'll look again for damaged wiring first, though.

As far as "killing the sensor". I doubt carb cleaner killed a sensor that can survive 500 degree heat. I'd imagine I damaged it when I used a propane torch on the manifold while forcing it to unscrew. Possibly that's the root of my problems.

FIXED! Installed new Denso O2 sensor, no more codes, no more problems. Runs great. Thanks for the troubleshooting steps guys, this time the fix wasn't the most probable one.