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P0155 Mercedes-Benz Code - O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1

Quick Answer

The P0155 code for Mercedes-Benz specifically indicates an issue with the O2 sensor heater circuit in Bank 2 Sensor 1. Common causes include Damaged wiring or connectors, Faulty O2 sensor, Blown fuse. 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 Mercedes-Benz indicates O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1.
Common causes
Common causes include Damaged wiring or connectors, Faulty O2 sensor, Blown fuse.
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 08, 2024
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Code P0155 Mercedes-Benz Description

The P0155 code for Mercedes-Benz specifically indicates an issue with the O2 sensor heater circuit in Bank 2 Sensor 1. The O2 sensor, also known as the oxygen sensor, plays a crucial role in monitoring the amount of oxygen in the exhaust gases and providing feedback to the engine control module (ECM) for optimal fuel efficiency and emission control. In this case, Bank 2 refers to the side of the engine that does not contain the number one cylinder.

OBDII Code P0155 Mercedes-Benz - O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1
P0155 Mercedes-Benz Code - O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1

Common Causes of P0155 Mercedes-Benz

  1. Damaged wiring or connectors
  2. Faulty O2 sensor
  3. Blown fuse
  4. ECM malfunction
  5. Corrosion or contamination on sensor

Symptoms of P0155 Mercedes-Benz

  1. Decreased fuel efficiency
  2. Rough idling or stalling
  3. Hesitation during acceleration
  4. Increased emissions
  5. Engine misfires

How to Fix P0155 Mercedes-Benz

  1. Diagnose the specific cause of the issue using an OBD-II scanner and multimeter to test the O2 sensor, wiring, and connectors.
  2. Replace the faulty O2 sensor if necessary. Ensure to use a high-quality, compatible sensor for optimal performance.
  3. Check and replace any damaged wiring or connectors in the O2 sensor heater circuit.
  4. Inspect and replace any blown fuses related to the O2 sensor heater circuit.
  5. Clear the error code from the ECM's memory and perform a test drive to ensure the issue has been resolved.

Cost to Fix P0155 Mercedes-Benz

The typical repair costs for addressing the P0155 code in a Mercedes-Benz can range from $150 to $500, depending on the specific cause of the issue and the cost of parts and labor. It's essential to consider the diagnosis time and labor rates at auto repair shops, which can vary based on location, vehicle make and model, and engine type. Rates typically range from $80 to $150 per hour, with variations in metropolitan areas, dealerships, and independent shops. To get a precise estimate, it's advisable to inquire about local rates before proceeding with the repair.

What does this mean?

Tech Notes for P0155 Mercedes-Benz

Mercedes Benz Code = 0437 (Left O2 sensor, before TWC): Short circuit to positive / Resistance of sensor heater too low (P0155)
Mercedes Benz Code = 0440 (Left O2 sensor, before TWC): Heating capacity is too low. (P0155)

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 takes the sensor to warm up and start sending an adequate signal. The code means 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)

Need more information about the P0155 Mercedes-Benz code?

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Need Help with the Code?

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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 Mercedes-Benz Code

1. What does the OBDII code P0155 Mercedes-Benz mean?

The code P0155 indicates an O2 sensor heater circuit malfunction on Bank 2 Sensor 1 in a Mercedes-Benz vehicle.

2. What are the common symptoms of O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 (P0155) in a Mercedes-Benz?

Common symptoms include decreased fuel efficiency, rough idling, engine misfires, and the illumination of the check engine light.

3. What are the possible causes of the O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 (P0155) in a Mercedes-Benz?

Possible causes may include a faulty O2 sensor, damaged wiring or connectors, a blown fuse, or issues with the engine control module.

4. How can I diagnose the O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 (P0155) in my Mercedes-Benz?

Diagnosis involves using an OBDII scanner to retrieve the error code, inspecting the O2 sensor and its connections, and checking the related fuses for continuity.

5. Can I continue driving my Mercedes-Benz with the O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 (P0155) code?

It is not recommended to drive your vehicle with the P0155 code as it can lead to decreased performance and potential damage to the catalytic converter.

6. How do I repair the O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 (P0155) in my Mercedes-Benz?

Repair typically involves replacing the faulty O2 sensor, repairing damaged wiring or connectors, or addressing any issues with the engine control module.

7. Are there any DIY tips for fixing the O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 (P0155) in a Mercedes-Benz?

While some simple tasks like checking and replacing fuses can be done by DIY enthusiasts, it is recommended to have a qualified mechanic diagnose and repair this issue.

8. How much does it cost to repair the O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 (P0155) in a Mercedes-Benz?

The cost of repair can vary depending on the specific issue and the labor rates in your area, but it typically ranges from $200 to $500 for parts and labor.

9. Will resetting the check engine light resolve the O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 (P0155) in my Mercedes-Benz?

Resetting the check engine light may temporarily turn it off, but it will not fix the underlying issue causing the P0155 code. It is important to diagnose and repair the problem to prevent further issues.

10. How often should the O2 sensors be inspected in a Mercedes-Benz to prevent O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1 (P0155) issues?

It is recommended to inspect the O2 sensors during regular maintenance intervals or whenever you experience symptoms like poor fuel efficiency or rough idling to prevent potential issues like the P0155 code.

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