2001 Toyota Echo P0141 O2 Sensor Heater Fault (Bank1 Sensor 2)

[phobios_p]

Hello,
I have a 2001 Toyota Echo. I took it to the smog test station and it failed the test. The guy said it failed because the check engine light is on and the computer showed this error: P0141 O2 Sensor Heater Fault (Bank 1 Sensor 2) Of course he only told me this after he charged me for the test.
In retrospect, it was very foolish on my part to take the car with a check engine light on.

Having said that this is what I plan on doing:

• I think this is the Oxygen sensor that is after the Catalitic converter so I plan first on taking it out and cleaning it. I also want to check the Ohms.
• Then I will put it back on and reset the computer by pulling the EFI Fuse B out.
• If the light is out I will drive the car for a while to see if this fixed the problem.
• If this does not work I will buy a new sensor and replace it.

Questions I have:
1.- Where is the EFI Fuse B?
2.- What should the Ohms be if the sensor is good?
3.- I heard about cleaning the Mass Airflow Sensor, is this a good idea?


I think this is where the O2 sensors are located: Toyota Questions & Auto Repair Information > Toyota Echo Questions > hard replace rear oxygen sensor - Just Answer!

Thanks

[mral1515]

That wont do you any good. The heater side of the sensor is bad. This means the heating element in sensor is either shorted out or has an open circuit. The sensor should have 4 wires. 2 are for the reading of oxygen content and the other 2 are for the heater unfortunatly this heater gets very hot very fast so it can put your vehicle in closed loop operation as soon as possible. After doing this over and over they will go bad.

As far as cleaning your mass air flow sensor. You can do that any time you want. They get dirt and grime on them and are unable to read the correct amout of air coming through the intake.

I don't remember where the efi fuse without looking at an Echo I couldn't tell you. It is either in the fuse box under the hood by the battery, or in the fuse box under the dash.

[phobios_p]

Thanks for your repply mral1515. So you recommend I replace the sensor then. What do you think of the ones they sell online? or should I pay the extra bucks and get the one from the dealer (4 times more expensive). Also, do you know where is the MAF Sensor I need to clean?
Thanks a lot!

[mustang67408]

As mral1515 said, the B1S2 is no good. The heater side of that sensor is probably burned out. Replace it with a TOYOTA one.
PM sent.
I have also attached a few diag sheets if you still want to check it, and a diag on the MAF and where it is located. BE CAREFUL when cleaning, the HOTWIRE inside of it is delicate, use electronic parts cleaner to clean it and let air dry, do not use compressed air.

The EFI fuse is under the hood drivers side fuse box.

[integraGSR]

P0141? I thought that a P0141 was a "System Too Lean"? If i'm not mistaking, a P0141 IS system too lean and needs a MAF sensor. are there any drivability issues? with a p0141, you vehicle should not have the same acceleration as it used to have.

[mustang67408]

Originally Posted by integraGSR

P0141? I thought that a P0141 was a "System Too Lean"? If i'm not mistaking, a P0141 IS system too lean and needs a MAF sensor. are there any drivability issues? with a p0141, you vehicle should not have the same acceleration as it used to have.

I am sorry but you are mistaken.
P0171 is system to lean. This will cause hesitations, hard start, poor mileage. (see attachment)

P0141 is

Heated Oxygen Sensor Heated Circuit
Malfunction (Bank1 Sensor2)
(see previous attachment)

[phobios_p]

Mustang, thanks a lot for your feedback and PDF files. As always, you give very sound and accurate advice. I will replace the sensor with an original one. Thanks again.

[integraGSR]

Originally Posted by mustang67408

I am sorry but you are mistaken.
P0171 is system to lean. This will cause hesitations, hard start, poor mileage.

whoops! that is correct. sorry, i saw 141 and just thought it was 171. nevermind... didn't realize it was P0141

[mustang67408]

Originally Posted by integraGSR

whoops! that is correct. sorry, i saw 141 and just thought it was 171. nevermind... didn't realize it was P0141

It's cool
No harm NO FOUL

[Tundra94x4]

I have a question about my 2001 tundra 4x4....i just had my bank 1 and 2 o2 sensors replace 20000 miles ago and now my check engine light is on again and i took it in to advanced auto to check it and they told me that my sensors on both sides are bad again.....i have a bad exhaust leak in my headers and i heard that a exhaust leak can through the o2 sensor off and make the check engine light come on...is that true? I have new Jba headers should i replace then and see what happens or replace the sensors?

[mek42]

Yes - fix the exhaust leak before replacing sensors.

Given, a snsor may still end up needing to be replaced, but many O2 sensor codes come from the difference between pre- and post- cat O2 levels - an air leak pre-cat will obviously make this a wrong reading and pop a code.

But, there may be something else wrong besides the air leak.

[special3ddie]

Is that read out indeed for the second sensor?