P0141

[T4R2014]

My 4Runner is WELL past the inspection date and I've got a P0141 code - bank 1 sensor 2 oxygen sensor heater curcuit. I replaced this sensor three years ago with a Denso. The light came on after installing a new exhaust but I left it since it was a rear sensor and it ran and still runs great. Well I need this light off for inspection(overdue by three months might I add - can you tell that this truck only gets 2000 miles in a year?).

So.. I got a new Denso sensor to replace the "bad" old sensor. Guess what, P0141 is back. I'm thinking it isn't the sensor at this point. Anyone dealt with this? I'm reading that it could be a bad ECU? Hopefully not. Any ideas? Perhaps a dirty connector?

Thanks.

 

[4Reak Show]

Year and engine please. I can then check on schematic for you and go from there.
999/1000 it's the sensor, but also I've seen some various vehicles with relays/fuses drop out as well and cause funky results. (And to ease woes, I've NEVER replaced ANY engine computer in 10 yrs general auto repair)

Also, we need to be sure you're replacing the right one. Easily confused with front/rear/left/right. That can also be confirmed with schematics so let me know year and engine please and I can walk you thru your options.

Good luck
-4Reak

 

[LittleCaesar]

For the PO141 I would say it is probably the kitty on its way out but check the wiring for the sensor as well as have a smoke test performed on the exhaust to check for leaks.

 

[4Reak Show]

Heater circuit code is not affected by cat performance

 

[californium90]

had the same issue, check and clean the MAF sensor as well, just to make sure, and then see what the O2 sensor looks like and may be replace both with denso ones from Amazon, I did that and the codes haven't come back since. Thank God for that! Phewwww.

 

[T4R2014]

Year and engine please. I can then check on schematic for you and go from there.
999/1000 it's the sensor, but also I've seen some various vehicles with relays/fuses drop out as well and cause funky results. (And to ease woes, I've NEVER replaced ANY engine computer in 10 yrs general auto repair)

Also, we need to be sure you're replacing the right one. Easily confused with front/rear/left/right. That can also be confirmed with schematics so let me know year and engine please and I can walk you thru your options.

Good luck
-4Reak

How clueless of me. It's a 1996 V6. SR5 if it matters. The code appears with two different Denso sensors. I gave a shot at cleaning the connector, so I'll see how that goes.

 

[WallyWest]

Check the wiring of the connector the sensor plugs into, if you haven't already. That's what screwed mine up, one of the wires was barely hanging on. Replaced that connector and it's been good since.

The 141 is just saying that it can't communicate with the sensor, if you've ruled out the sensor then it's likely a wiring short somewhere.

My record for driving without inspection is 2.5 years. Daily driver, didn't get stopped at all. If you can stick to night driving, forget about it. LOL

 

[4Reak Show]

1996 means simple. Heater circuit is simple power and ground at 2 of the terminals.

Use this as a reference to ensure you've replaced the correct sensor. The wire colors indicate HARNESS side, not SENSOR side of the connector. If you think you've replaced the correct one, next step for a proper diag: key on, engine off with connector disconnected and check at the Red/White & White/blue wire pins with a voltmeter. Should read about battery voltage (12v) (Positive lead on white wire w/ blue stripe, negative on the other).

Could very well be a loose pin, corroded connector something like that. Look really good at the connector. Worst comes to worse, going to Toyota with Vin will guarantee exact right sensor and then there's no doubt on quality.

 

[T4R2014]

OK. Sprayed the piss out of the connector with contact cleaner. Plugged the sensor back in. Knock out wood, but no light yet. It's only been 15 miles but if it stays off and the monitors are ready then I'm going for inspection.