AutoCodes – Honda – P0155 Honda

P0155 Honda Code - A/F Sensor 21 Heater System Malfunction

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 Honda indicates A/F Sensor 21 Heater System Malfunction.
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 29,840

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
FAQs
Comments
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Code P0155 Honda 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 Honda - A/F Sensor 21 Heater System Malfunction - AutoCodes.com — P0155 Honda Code - A/F Sensor 21 Heater System Malfunction

What does this mean?

What are the Possible Causes of the DTC P0155 Honda?

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 Honda?

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 Honda 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 Honda Code

1. What are the common symptoms of OBDII code P0155 in a Honda related to the A/F Sensor 21 Heater System Malfunction?

- Common symptoms include poor fuel economy, rough idle, hesitation during acceleration, and an illuminated check engine light.

2. What are the possible causes of the P0155 code in a Honda, indicating an issue with the A/F Sensor 21 Heater System?

- Possible causes include a faulty A/F sensor, damaged wiring or connectors, a blown fuse, or a problem with the PCM (Powertrain Control Module).

3. How can I diagnose the P0155 code in my Honda related to the A/F Sensor 21 Heater System Malfunction?

- You can diagnose the issue by checking the wiring and connectors for damage, testing the A/F sensor's heater circuit, and inspecting the fuse related to the sensor.

4. Can I continue to drive my Honda with the P0155 code related to the A/F Sensor 21 Heater System Malfunction?

- It is not recommended to drive your vehicle with this code illuminated, as it can lead to further damage and potentially affect the engine's performance.

5. How can I repair the P0155 code in my Honda caused by the A/F Sensor 21 Heater System Malfunction?

- Repair options include replacing the faulty A/F sensor, repairing any damaged wiring or connectors, checking and replacing the fuse if necessary, or addressing any PCM issues.

6. Are there any DIY tips for fixing the P0155 code in a Honda related to the A/F Sensor 21 Heater System Malfunction?

- DIY tips include ensuring the sensor is properly connected, checking for any visible damage to the wiring, and consulting the vehicle's service manual for specific repair steps.

7. How much does it typically cost to repair the P0155 code in a Honda due to the A/F Sensor 21 Heater System Malfunction?

- The cost of repair can vary depending on the exact cause of the issue, but it may range from $100 to $300 for parts and labor.

8. Can a P0155 code related to the A/F Sensor 21 Heater System Malfunction be triggered by a loose gas cap in a Honda?

- While a loose gas cap is more likely to trigger a different code related to the fuel system, it is still a good idea to check and ensure the gas cap is properly tightened.

9. Will resetting the check engine light clear the P0155 code in a Honda with an A/F Sensor 21 Heater System Malfunction issue?

- Resetting the check engine light may temporarily turn it off, but the underlying issue causing the P0155 code will still need to be diagnosed and repaired to prevent future occurrences.

10. Is it safe to ignore the P0155 code in a Honda related to the A/F Sensor 21 Heater System Malfunction?

- Ignoring the code can lead to decreased fuel efficiency, potential engine damage, and may cause the vehicle to fail an emissions test, so it's best to address the issue promptly.