o2 sensor diagnosed: Code P0141

**Gladiator** · 08-09-2007, 05:38 PM

Went to Autozone today and gave them the code P0141
This is what their computer printed out:

The PCM has determined that a malfunction exists in the heater circuit for oxygen sensor 2 in bank 1. (Oxygen sensor 1 is closest to the cylinder head before the catalytic converter, while oxygen sensors 2 & 3 are located further downstream and are typically mounted in or after the catalytic converter) (bank 1 identifies the location of cylinder #1, while bank 2 identifies the cylinders on the opposite bank).

If I try to replace the sensor myself, where is sensor 2 located? Do we have 2 sensors by the cat?

Thanks

**GarciaR88** · 07-09-2012, 08:31 PM

Has no one replied to this? I have the same issue, same code. Would like to know where this sensor is? Does it mean that there are 4 sensors total?

In my case, top 2 have been replaced, but still getting this code.

**Isaurio** · 07-09-2012, 09:23 PM

2.4l or v6?

**GarciaR88** · 07-13-2012, 12:05 PM

V6. Had sensor replaced. Code came back after car was turned off. Does the PCM need to be reset? Do I need to check fuses?

**bgood12** · 07-13-2012, 05:30 PM

Usually you either need to take off negative battery terminal of have code erased and then see if it comes back.

**GarciaR88** · 07-13-2012, 10:59 PM

Code was removed using code reader tool. Was that not enough? I know the new O2 sensor was installed without negative cable being removed from battery.

**John165** · 07-14-2012, 11:09 AM

Originally Posted by GarciaR88

V6. Had sensor replaced. Code came back after car was turned off. Does the PCM need to be reset? Do I need to check fuses?

Just curious, did you check to see if heater on the sensor was open? Or that the battery voltage was available for the heater? I have another car to check with basically the same code. And so I was wondering what threw your code. And I see that your code came back, I just unplugged my battery for about 10 minutes and it resets my code. It comes back thou lol. A problem exists with mine that I need to fix.

And one more thing, I read on here cant remember where from a poster who recommends letting the car Idle for 10 minutes or so after resetting code, to let the PCM get used to the readings from the new sensor and or relearn stuff. You think the reader deleteing the code should be enough, try unhooking the battery, like I did. That will reset it for sure.

**GarciaR88** · 07-17-2012, 06:38 PM

Thanx John165. I have no idea. I bought the car used. Guy I bought it from said they knew about the code. Changed two top side O2 sensors, but the needed to change the one after the catalytic converter. Had is changed out last Thursday, reset code, drove it to work, got in after work... light came back on. Went to Auto Zone for code check... same code P0141.

Going to try disconnecting the battery. Post results later.

**GarciaR88** · 07-17-2012, 07:56 PM

After disconnecting negative cable for 10 min... light still on. Anyone know if this will pass inspection in state of TX?

**bgood12** · 07-17-2012, 11:59 PM

Man I'm from Dallas, ask around find a shop you know tell them what's up see if they can fix it and of they can't tjhey will pass you, I used to get hookups on them cause I'm not buying tires and shit to pass inspection on top of paying for tags and shit all at once.

**bronxbombr** · 07-18-2012, 12:37 PM

If you need the sensors i have a very high quantity of 7G and 8G O2 sensors for sale

**GarciaR88** · 07-18-2012, 04:18 PM

@ bgood12: Thanks. I plan on looking around for a shop where my parents live.

@ bronxbombr: Thanks for the offer. I've seen posts about the Bosch sensors being crap. That's what got installed after the cat. Any thoughts?

**bronxbombr** · 07-19-2012, 11:30 AM

I have bosch and I have Standard OEM brands

**GarciaR88** · 07-19-2012, 03:31 PM

@bronxbombr: How many O2 sensors on V6?

**Reelax** · 07-19-2012, 04:00 PM

fed spec or cali spec?

**GarciaR88** · 07-19-2012, 06:35 PM

@Reelax: Aren't they all Cali spec? How can I tell what I have?

**John165** · 07-19-2012, 09:59 PM

I dont know about the Bosch sensors, but It seems some cars dont like them. I def know that Dodges dont. I dont know about Mitsubishi. If I replace mine, I would go with the Densos at AAP's

The service manual says:

DTC P0141: O2 Sensor Heater Circuit Malfunction (bank 1 sensor 2)

CIRCUIT OPERATION
• Power is supplied from the MFI relay (terminal 1)
to the right bank heated oxygen sensor (rear)
heater.
• The PCM (terminal 27) controls continuity to the
right bank heated oxygen sensor (rear) heater by
turning the power transistor in the PCM "ON" and
"OFF."

"TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are:)
• Open or shorted right bank heated oxygen
sensor (rear) heater circuit.
• Open circuit in right bank heated oxygen sensor
(rear) heater.
• PCM failed."

The checks for this code are pretty basic, you just take a volt meter and probe the pins of the oxygen sensor connecot to make sure internally that the heater isnt "open" aka broke. And that the engine harness connector to the sensor has battery voltage with key on.

The sensor should have 4 pins, two of those pins is the heater and the other two is for the sensor to tell the computer to lean the fuel mixture or richen it.

You check the pins for the heater for so many ohms. If the resistance checks ok, you make sure there is battery voltage coming to the sensor from the MFI relay. I think the other wire is the ground to finish the circuit.

You can do this yourself, just use CAUTION not to damage the pins of the sensor or the wire harness. All you gotta do is barely touch the pins just enough to get a reading. All this info is in the service manual under stickys. It can be hard to navigate at first but I have allready found it, and can tell you what pages this info is under. The reason I know is because my code is for the CAT and I have been reading the service manual for it.

Oh and the manual tells you what pins to checks except it stats using a special harness, to check the resistance of the sensor. In my opinion, (im no mechanic) that harness is not needed for that check, and that the reason I think it calls for it is to ensure no damage is done to the pins and or connectors. Maybe someone else can confirm whether or not that harness is needed for that check. If it is, well then I guess a shop or the dealer would be best for checking the sensor heater.

If your good with those hand held multi meters, I would check for battery voltage at the connector like the manual stats.

**Reelax** · 07-19-2012, 11:55 PM

Originally Posted by GarciaR88

@Reelax: Aren't they all Cali spec? How can I tell what I have?

well starting in 2002 all USDM 8G's were made cali spec, but from 1999-2001 the USDM 8G was available outside of california in a fed spec version with no pre-cats and less o2 sensors.

https://www.thegalantcenter.org/showthread.php?t=15204

additionally, here is a picture of my cali spec v6 exhaust from after the manifolds to the cat back section off the car (the sliver piping was a prototype downpipe i was testing for our cars). if your exhaust looks like this u have a cali spec v6 (the small pre-cats are the dead giveaway):