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P0155 OBD II Trouble Code

If the Verify Engine Light is certainly illuminating your dashboard and the OBD-II reader is displaying P0155, you probably want to know what this code means. If youre only interested in the codes most basic definition, well cut to the chase: its “O2 Sensor Heater Circuit Malfunction (B2S1)”. If, on the other hand, you want to know more, including the codes meaning, potential causes and exact diagnostic and repair steps, keep on reading.

The Meaning and Cause of the P0155 Code

The P0155 Diagnostic Trouble Code (DTC) is usually a generic powertrain code, meaning it applies to all vehicles equipped with the OBD-II system. Although generic, the specific repair steps for this DTC will vary from model to model (of the vehicle).

Back to that definition: “O2 Sensor Heater Circuit Malfunction (B2S1)”. To understand what the P0155 means, we need to break this down. Obviously, the 02 sensor part refers to the oxygen sensor; circuit malfunction is clear enough – somethings not working properly in the oxygen sensor circuit. As for those letters and figures, B2 and S1, they refer to the bank and the sensor, respectively. So the B2 refers to the Bank 2, but to find it, you have to know where the Lender 1 is. Luckily, thats not too hard, as the Bank 1 refers to the side of the engine that has the #1 cylinder; Lender 2 is therefore on the opposite side of the engine. If your vehicle has a four-cylinder, there is only one bank, which means you wouldnt get this code. As for S1 part of the definition, it refers to sensor #1.

But what causes the P0155 code?

There can be several known reasons for this DTC showing up, however the most common causes consist of:

  • Internal brief or bare cable resulting in the O2 sensor
  • Faulty air sensor on Loan company 2
  • O2 sensor heating unit element includes a high level of resistance
  • O2 sensor heating unit element comes with an open up circuit
  • Broken wiring/loose cable connections
  • Brief or available to the bottom in the wiring funnel
  • ECT sensor no longer working properly
  • Power control component not working correctly (uncommon).

So essentially, whenever your OBD-II audience/scanning device reveals the P0155 DTC, this means that whenever your vehicles powertrain control module acquired examined the O2 sensors heating unit circuit on Loan company 2, it observed an excessive level of resistance or brief in the heating unit element. This means O2 sensor acquiring longer to warm up and enter shut loop.

heating unit

The Symptoms from the P0155 Code

Normally, a failed O2 sensor network marketing leads to poor gasoline economy, nevertheless, its entirely possible to experience no symptoms at all when the P0155 code shows up, except for the illuminated Check Engine Light. Still, most drivers will experience a combination of the following symptoms:

heating unit
  • Check Engine Light is usually on
  • Decreased gas economy
  • The engine may run rough
  • There may be a sulfur smell coming from the exhaust
  • There may be black smoke coming out of the exhaust.

Diagnosing and Fixing the P0155 code

In most cases, when the P0155 DTC shows up, the O2 sensor needs to be replaced. However, this is not always required, as sometimes the problem can lie in the catalytic converter, or an exhaust leak or damaged wiring or connections. For this reason, its crucial to inspect your vehicle thoroughly and pay attention not only to the O2 sensor, but to the other components of the car as well. However the P0155 code isn’t among the critical malfunctions, its still vital that you invest some time to correctly inspect, fix and test the automobile. So, if you don’t have a substantial amount of motor vehicle knowledge, its smart to let a specialist fix your vehicle.

Regardless, this is what you or your auto mechanic must do to inspect your automobile and repair the P0155 DTC:

  • Plug the OBD-II scan device in the DLC interface and be aware all stored rules and freeze body data. Having this information is crucial as it can reveal the condition of the automobile at the time when the P0155 code 1st showed up.
  • Inspect the wiring that leads to the O2 sensor. Look for damaged or bare wires and restoration or replace items as necessary.
  • Test the O2 sensor for appropriate voltage using a multimeter (of course, consult the instructions from your car restoration manual 1st).
  • If you find a damaged sensor or wiring, repair it and use the scan tool to view live data in order to make sure the O2 sensor is definitely working as it should. If the O2 sensor appears to be in good condition and is operating as it should, leave things because they are and check out the next phase.
  • Verify the engine surface to check out corrosion, harm and loose cable connections. Remove corrosion, fix and tighten stuff as required and restart the diagnostic procedure.
  • If the ECT sensor isn’t working since it should, the energy control component will shop this code as well, in which particular case youll wish to cope with it.
  • Sometimes, the energy control component itself could possibly be the issue. In this uncommon case, advanced inspection and medical diagnosis is essential, which isn’t a job for the layman.

To correctly diagnose and fix the P0155 code, an intensive inspection is crucial. Frequently, people will replace the O2 sensor before inspecting various other components which simply leads to raised fix costs and irritation.

To summarize, the following fixes can repair the P0155 DTC:

  • Fixing broken/replacing bare wires
  • Replacing the O2 sensor
  • Replacing the ECT sensor
  • Rarely, replacing the power control module.

Additional Information about the P0155 Code

Because the code P0155 doesnt present danger to the driver, its not regarded as a serious DTC. It is, however, a moderately severe code. This is because it often causes drivability issues and poor gas economy. Plus, the longer you wait to fix it, the higher the restoration costs will become. Needless to say, its wise to cope with this code once you see it.

In the event that you dont very own an air sensor established and a propane container, removing the air sensor could be tricky. Because of this, its smart to let a specialist diagnose and fix the P0155 code.

Code Explanations

These links provides more descriptive insights into what code means in your automobile:

Make sure to also read our important guide to the very best OBD2 Scanner.

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