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P0155 Lexus Code - O2 Sensor Heater Circuit Bank 2 Sensor 1

Quick Answer

The P0155 diagnostic trouble code (DTC) for Lexus vehicles specifically indicates an issue with the O2 sensor heater circuit for Bank 2 Sensor 1. Common causes include Faulty O2 sensor heater circuit, Wiring or connector issues, Blown fuse related to the O2 sensor heater. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means
P0155 Lexus indicates O2 Sensor Heater Circuit Bank 2 Sensor 1.
Common causes
Common causes include Faulty O2 sensor heater circuit, Wiring or connector issues, Blown fuse related to the O2 sensor heater.
Severity
Moderate - service should be scheduled soon.
Can I drive?
The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code P0155 Lexus Description

The P0155 diagnostic trouble code (DTC) for Lexus vehicles specifically indicates an issue with the O2 sensor heater circuit for Bank 2 Sensor 1. This sensor is responsible for measuring the oxygen content in the exhaust gases and providing feedback to the engine control module (ECM) to adjust the air-fuel mixture for optimal combustion. The heater circuit within the O2 sensor is designed to reach operating temperature quickly to ensure accurate readings, especially during cold starts.

OBDII Code P0155 Lexus - O2 Sensor Heater Circuit Bank 2 Sensor 1
P0155 Lexus Code - O2 Sensor Heater Circuit Bank 2 Sensor 1

Common Causes of P0155 Lexus

  1. Faulty O2 sensor heater circuit
  2. Wiring or connector issues
  3. Blown fuse related to the O2 sensor heater
  4. ECM malfunction
  5. Exhaust leaks affecting O2 sensor operation

Symptoms of P0155 Lexus

  1. Decreased fuel efficiency
  2. Rough idling or hesitation during acceleration
  3. Engine stalling
  4. Increased emissions
  5. Check Engine Light illuminated on the dashboard

How to Fix P0155 Lexus

  1. Begin by diagnosing the specific cause of the P0155 code using a scan tool to pinpoint the issue with the O2 sensor heater circuit.
  2. Inspect the wiring and connectors associated with the O2 sensor for any damage or corrosion. Repair or replace as needed.
  3. Check the fuse related to the O2 sensor heater circuit and replace if blown.
  4. Test the O2 sensor itself to determine if it is functioning correctly. Replace the sensor if necessary.
  5. Clear the code from the ECM memory and perform a test drive to ensure the issue has been resolved.

Cost to Fix P0155 Lexus

The typical repair costs for addressing a P0155 code on a Lexus vehicle can range from $150 to $400, depending on the specific cause of the issue and the cost of parts and labor. It's important to note that diagnosis time and labor rates at auto repair shops can vary, with hourly rates typically ranging between $80 and $150. Factors such as location, vehicle make and model, and engine type can also impact the final repair costs. For a more accurate estimate, it is recommended to consult with local auto repair shops.

What does this mean?

Tech Notes for P0155 Lexus

The code means that there is a problem with the heater element circuit of the heated oxygen sensor. The Engine Control Module (ECM) monitors how long it take the sensor to warm up and start sending an adequate signal. The code means the the sensor is taking too long to warm up. Replacing the Front Heated Oxygen Sensor (H2OS) Bank 2 usually takes care of the problem.

When is the Code Detected?

The current amperage in the front heated oxygen sensor heater circuit is out of the normal range. (An improper voltage drop signal is sent to ECM through the front heated oxygen sensor heater)

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0155 Lexus Code

No Frequently Asked Questions about P0155 Lexus Code found.

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  • I Replace the sensor .2 mile of driving it the check engine light returned Any idea why that happens thanks

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  • You got the same code? If you do, I'll start by checking the O2 sensor connector. What model and year is your vehicle?

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  • Lexus is 300 2001 yes same code

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  • Unfortunately I never had that problem before, but I checked a national database or repairs for your model year and out 169 repairs, 166 the O2 sensor fixed the problem, 2 the Engine Control Module and 1 time the problem was the wire harness.

    Reply to Comment

  • OK thanks

    Reply to Comment