Rear Oxygen Sensor Heater Test -P0141 (1997-2001 2.0L Honda CR-V)

This tutorial will help you to diagnose a P0141 on your 2.0L Honda CR-V. Although this code usually means that you need to replace the rear O2 sensor, sometimes you've got to make sure that its heater element is getting power and ground.

This tutorial will explain how to make sure the rear O2 sensor is getting power and ground and how to test the resistance of the heater element itself. All pretty simple tests explained in a step-by-step way.

By the way you don't need any fancy (expensive) diagnostic equipment for these tests, just a multimeter will do.

Here are the contents of this tutorial:

  1. Circuit Descriptions Of The Downstream Oxygen Sensor.
  2. TEST 1: Verifying Power And Ground.
  3. TEST 2: Testing The Heater Element's Resistance.
  4. Where To Buy The Oxygen Sensor And Save.
  5. More 2.0L Honda Tutorials.

En Español You can find this tutorial in Spanish here: Cómo Probar El Código P0141 (1997-2001 2.0L Honda CR-V) (at: autotecnico-online.com).

NOTE: If you need to test the front oxygen sensor's heater (trouble code P0135), see the following tutorial: Oxygen Sensor Heater Test -P0135 (1997-2001 2.0L Honda CR-V).

Circuit Descriptions Of The Downstream Oxygen Sensor

Circuit Descriptions Of The Downstream Oxygen Sensor -P0141 (1997-2001 2.0L Honda CR-V)

The rear O2 sensor has 4 wires sticking out of it. To confirm that it's getting power and ground, we need to know which two wires to test.

So in the table below you'll find a brief description of each of the four wires that connect to the rear O2 sensor.

The one thing that you need to keep in mind is that the O2 sensor engine wiring harness connector has female terminals. While the terminals on the O2 sensor connector itself are male terminals.

Here's a brief description of the 4 wires of the front oxygen sensor:

Downstream Oxygen Sensor -1997 To 2001
Pin Wire Color Description
1 WHT/RED O2 Signal
2 GRN/WHT O2 Signal
3 BLK/WHT Heater Power (+)
4 BLK/WHT Heater Ground (-)

TEST 1: Verifying Power And Ground

Verifying Power And Ground To The Rear Oxygen Sensor -P0141 (1997-2001 2.0L Honda CR-V)

To get our P0141 diagnostic on the road, we're gonna' make sure that the rear O2 sensor's heater element is getting power and ground.

To get into specifics: we're gonna' make sure that the black with white stripe (BLK/WHT) wire is feeding the heater element power.

We're also gonna' sure that the black with white stripe (BLK/WHT) wire is feeding the heater element with ground (yup, both wire are the same colors).

CAUTION: Perform all O2 sensor tests with a completely cold engine. The O2 sensor gets and stays hot for a long time after engine shut down. So if your Honda CR-V's engine has been running for any amount of time, let it cool down completely before you start. Also, if you raise the vehicle to access the O2 sensor, place it on jack stands.

IMPORTANT: The pinout in the illustration above is of the connector on the oxygen sensor itself. To check for power and ground, you'll test the two indicated wires of the engine wiring harness sensor connector.

OK, this is what you'll need to do:

  1. 1

    Locate the upstream oxygen sensor and disconnect it from its engine wiring harness connector.

  2. 2

    Set your multimeter to Volts DC mode and turn the key On but don't crank or start the engine (this will power up the O2 sensor's engine wiring harness connector).

  3. 3

    Make sure that the BLK/WHT wire (terminal #3) is feeding battery power.

    Connect the red multimeter lead to the BLK/WHT wire and connect the black multimeter lead to the battery ground (-) terminal.

    Your multimeter should read 10 to 12 Volts DC.

  4. 4

    Make sure that the BLK/WHT wire (terminal #4) is feeding Ground. This ground is provided by the PCM.

    Connect the black multimeter lead to the BLK/WHT wire and connect the red multimeter lead to the battery positive (+) terminal.

    Your multimeter should read 10 to 12 Volts DC.

Let's take a look at your test results:

CASE 1: Your multimeter registered 10 to 12 Volts DC- This is the correct and expected test results.

Now that you have confirmed that the rear O2 sensors heater element is getting power and ground. The next step is to check the heaters resistance with a multimeter. For this test go to: TEST 2: Testing The Heater Element's Resistance.

CASE 2: Your multimeter DID NOT register 10 to 12 Volts DC- the most likely cause of this missing power is a blown fuse. Check fuse number in the fuse box and make sure it's not blown.

If the fuse is blown, replace it and repeat this test section.

CASE 3: The heater element is not getting ground. The most likely cause of this missing ground is an open in the wiring between the O2 sensor's engine wiring harness connector and its ground point. Although it's beyond the scope of this tutorial to test for this missing ground, your next step is to do a continuity test between the O2 sensor ground wire and Chassis ground.