When a P0141: Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2) lights up the check engine light on your 2.2L Honda Accord (Odyssey), it's usually because the rear oxygen sensor's heater has failed.
In this tutorial, I'll explain what this trouble code means. I'll also talk about some of the tests you can perform to find its cause and solution.
Contents of this tutorial:
You can find this tutorial in Spanish here: Código P0141 ¿Qué Significa? (1995-1997 2.2L Honda Accord, Odyssey) (at: autotecnico-online.com).
APPLIES TO: This tutorial, on the P0141 OBD II trouble code, applies to the following vehicles:
- 2.2L Honda Accord (DX, EX, LX): 1995, 1996, 1997.
- 2.2L Honda Odyssey: 1995, 1996, 1997.
What Does Trouble Code P0141 Mean?
A P0141: Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2) means that the rear oxygen sensor's heater is not heating up the oxygen sensor anymore.
The rear oxygen sensor is located after the catalytic converter and is known by several different names:
- HO2S-2 (Heated Oxygen Sensor -2).
- Downstream Oxygen Sensor (downstream from catalytic converter).
- Bank 1 Sensor 2.
- Oxygen Sensor 2.
Common Symptoms Of A P0141 Trouble Code
When the rear oxygen sensor's heater fails on your 2.2L Honda Accord (Odyssey), it generally does not cause any drive-ability problems.
For the most part, the only thing noticeable is an illuminated check engine light on your Honda Accord or Odyssey's instrument panel.
Also, a P0141 trouble code will cause the vehicle to fail an emissions test.
What Does The Rear O2 Sensor's Heater Do?
The oxygen sensor needs to reach a temperature of about 650° F to begin sensing the oxygen content of the exhaust it's exposed to in the tailpipe.
Once the O2 sensor reaches its operating temperature and starts sensing the oxygen content of the exhaust, the fuel injection computer can start making air/fuel mixture adjustments.
And as you're probably already aware, this adjustments in turn reduce harmful tailpipe emissions and optimizes engine fuel consumption.
Unfortunately, the exhaust gas may not be hot enough to get the O2 sensor to activate nor maintain it at its operating temperature.
This is where an internal heater saves the day, since it starts to heat the oxygen sensor as soon as the engine is started.
The heater also maintains the oxygen sensor at its operating temperature throughout all engine operating conditions.
What Causes A P0141 Trouble Code?
In the majority of cases, this trouble code appears because the internal heating element of the rear oxygen sensor has failed.
Other causes of a P0141 trouble code are:
- Blown oxygen sensor heater fuse.
- Rear oxygen sensor wires have melted and shorted together (this is usully due to the wires coming in contact with the exhaust pipe).
How To Diagnose And Repair A P0141 Trouble Code
As mentioned earlier, troubleshooting and solving a trouble code P0141 generally involves replacing the rear oxygen sensor with a new one.
Although not an absolute must, I usually check the heater element's internal resistance (with a multimeter in Ohms mode) and compare it to the factory specification.
If the heater element's resistance value is not within the indicated specification, then I now have the certainty that replacing it with a new will solve the trouble code.
When replacing the rear oxygen sensor, I recommend that you:
- Visually inspect the rear oxygen sensor's wiring for damage or signs of the wires short-circuiting together.
- Check the oxygen sensor heater fuse (if blown, replace it).
CAUTION: Any troubleshooting or replacement of the oxygen sensor must be done with a completely cold engine. Use jack stands to support the vehicle -don't trust the jack! Lastly, use safety glasses when working underneath the vehicle.
Where To Buy The Rear O2 Sensor And Save
The following links will help you comparison shop for the rear oxygen sensor:
More 2.2L Honda Accord And Odyssey Tutorials
You can find a complete list of 2.2L Honda tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Test The MAP Sensor (1994-1997 2.2L Accord, Odyssey, Prelude).
- How To Test The Head Gasket (1992-1997 2.2L Accord, Odyssey, Prelude).
- How To Test The Engine Compression (1992-1997 2.2L Accord, Odyssey, Prelude).
- How Often Should I Replace The Spark Plugs? (2.2L Honda Accord).
If this info really saved the day, buy me a beer!