How To Diagnose A P0141 Heater Performance Bank 1 Sensor 2

TEST 1: Checking 12 Volts To O2 Heater

OK, the first order of business is to make sure that the O2 sensor's heater element is getting power.

This power comes in the form of 10 to 12 Volts from the 02 sensor fuse in the engine compartment fuse box.

NOTE: Although the image I'm using shows the O2 sensor connector, you'll be testing the circuits of the O2 sensor harness connector. The O2 sensor harness connector is the connector on the engine wiring harness.

OK, to get our P0141 troubleshooting under way, this is what you need to do:

1. Jack up the vehicle and support it on jack stands.
   • Never trust the jack to hold up the vehicle. Use jack stands!
2. Disconnect the rear oxygen sensor.
   • Your vehicle has 2 oxygen sensors, one before the catalytic converter and one after it.
   • The O2 sensor that we're testing is the one after the catalytic converter.
3. Locate the Pink wire
   • The Pink wire is the circuit D wire of the engine wiring harness oxygen sensor connector.
   • The letter D will be embossed on the connector too.
4. With the Key On Engine Off, this wire should have 10 to 12 Volts DC.

Let's take a look at your test results:

CASE 1: 10 to 12 Volts are present in the Pink wire. This tells you that you that the heater element within the oxygen sensor is getting power.

The next step is to make sure that the PCM is Grounding circuit C. For this test, go to: TEST 3: Checking The O2 Heater's Ground Circuit.

CASE 2: 10 to 12 Volts ARE NOT present in the Pink wire. This usually means that the O2 sensor fuse, in the Engine Compartment Fuse Box is blown.

Check the fuse and if blown, replace it and retest.

NOTE: Usually, when the fuse is blown, you'll also see a P0135 DTC too, since this fuse also feed the front oxygen sensor with power.

TEST 3: Checking The O2 Heater's Ground Circuit

So far, you've reached this point because you have confirmed that the O2 sensor heater element is getting power (on the Pink wire which is the C circuit of the 02 sensor).

In this part of the P0141 Test, you'll make sure that the PCM is providing a Ground on the Black w/ White stripe wire of the engine wiring harness oxygen sensor connector.

The Black w/ White stripe wire is the circuit C of the oxygen sensor connector (and you'll find this letter embossed on the connector itself).

NOTE: Although the image I'm using shows the O2 sensor connector, you'll be testing the circuits of the O2 sensor harness connector. The O2 sensor harness connector is the connector on the engine wiring harness.

These are the test steps:

1. Disconnect the rear oxygen sensor (if it isn't already from TEST 2).
2. Locate the circuit C wire.
3. Place your multimeter in Volts DC mode and:
   • Connect the red multimeter test lead to battery (+).
   • Connect the black lead to the circuit C wire of the engine wiring harness O2 sensor connector.
4. With the Key On Engine Off, this wire should have 10 to 12 Volts DC.

Let's take a look at your test results:

CASE 1: The multimeter registered the indicated voltage. This tells you that you that the heater element within the oxygen sensor is getting Ground.

The next step is to check the resistance of the oxygen sensor's heater element to see if it has an open-circuit problem. For this test, go to: TEST 4: Checking The O2 Heater Element's Resistance.

CASE 2: The multimeter DID NOT register the indicated voltage. This tells you that the PCM is bad (although this is extremely rare) or the wiring between the O2 sensor and the PCM has an open-circuit problem.

Although it's beyond the scope of this article, the next step for you is to check the continuity of this Black w/ White stripe wire between the O2 sensor connector and the PCM's connector.

TEST 4: Checking The O2 Heater Element's Resistance

Alright, so far you have checked and confirmed that the O2 sensor's heater element is getting both power and Ground.

The very last thing we now need to do, is to check to see if the heater element (inside the oxygen sensor for Bank 1 Sensor 2) is fried or not.

This is a very simple and easy test that you can accomplish with your multimeter in Ohms mode.

NOTE: You'll be testing the circuits of the connector of the O2 sensor itself and not the O2 sensor harness connector (that's part of the engine wiring harness).

OK, this is what you need to do:

1. Disconnect the oxygen sensor from the engine wiring harness connector (if it isn't already from the previous tests).
2. Locate the O2 sensor wires that correspond to:
   1. The circuit C.
   2. -AND-
   3. The circuit D.
   4. Both of these letters should be embossed on the O2 sensor's connector to aid you in further identifying the circuits you need to test.
3. With your multimeter in Ohms mode, check the resistance of this circuit.
   • NOTE: Remember, you're testing the oxygen sensor itself.
   • If all is OK, you should see about 4.5 Ω (Ohms).
   • If the heater element is fried, your multimeter will show an open (usually indicated by the letters OL).

Let's take a look at your test results:

CASE 1: Your multimeter showed the indicated resistance. This tells you that you that the heater element within the oxygen sensor is OK.

CASE 2: Your multimeter DID NOT show the indicated resistance. This tells you that you that the heater element is fried. The oxygen sensor needs to be replaced.