AutoCodes – Lexus – P0155 Lexus

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

Quick Answer

Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. Common causes include Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1, Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 circuit fuse, Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 harness is open shorted to ground. 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 Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1, Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 circuit fuse, Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 harness is open shorted to ground.
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.

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Code Popularity 29,177

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 23, 2024

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0155 Lexus Description

Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. The faster the heated oxygen sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM). In order to achieve the require temperature, a heater element is included inside the heated oxygen sensor. The ECM controls the heated oxygen sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground. The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.

OBDII Code P0155 Lexus - O2 Sensor Heater Circuit Bank 2 Sensor 1 - AutoCodes.com — P0155 Lexus Code - O2 Sensor Heater Circuit Bank 2 Sensor 1

What does this mean?

What are the Possible Causes of the DTC P0155 Lexus?

Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1
Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 circuit fuse
Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 harness is open shorted to ground
Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0155 Lexus?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0155 Lexus code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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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Ernesto
Date: August 4, 2018 at 4:46 pm

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

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OBDIITech
Date: August 4, 2018 at 6:09 pm

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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Ernesto
Date: August 4, 2018 at 9:48 pm

Lexus is 300 2001 yes same code

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OBDIITech
Date: August 5, 2018 at 3:12 am

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.

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Ernesto
Date: August 7, 2018 at 2:01 pm

OK thanks

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