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Engine-Codes – Toyota – P1155 Toyota

P1155 Toyota Code - Air/Fuel Ratio Sensor Heater Circuit Malfunction Bank 2 Sensor 1

Quick Answer

The P1155 diagnostic trouble code (DTC) for Toyota vehicles indicates a malfunction in the air/fuel ratio sensor heater circuit for bank 2 sensor 1. Common causes include Faulty Sensor: The air/fuel ratio sensor itself may be faulty and require replacement, Wiring Issues: Damage or corrosion in the wiring harness connected to the sensor can disrupt the heater circuit, ECM Malfunction: A malfunction in the engine control module (ECM) could prevent the proper operation of the sensor heater. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1155 Toyota indicates Air/Fuel Ratio Sensor Heater Circuit Malfunction Bank 2 Sensor 1.
Common causes
Common causes include Faulty Sensor: The air/fuel ratio sensor itself may be faulty and require replacement, Wiring Issues: Damage or corrosion in the wiring harness connected to the sensor can disrupt the heater circuit, ECM Malfunction: A malfunction in the engine control module (ECM) could prevent the proper operation of the sensor heater.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P1155 Toyota Description

The P1155 diagnostic trouble code (DTC) for Toyota vehicles indicates a malfunction in the air/fuel ratio sensor heater circuit for bank 2 sensor 1. This sensor is responsible for measuring the oxygen content in the exhaust gases and helping the engine control module (ECM) adjust the air-fuel mixture for optimal combustion. The heater circuit is crucial for the sensor's proper operation, especially during cold starts when the sensor needs to reach operating temperature quickly. A malfunction in this circuit can lead to inaccurate sensor readings, affecting the engine's performance, fuel efficiency, and emissions.

OBDII Code P1155 Toyota - Air/Fuel Ratio Sensor Heater Circuit Malfunction Bank 2 Sensor 1
P1155 Toyota Code - Air/Fuel Ratio Sensor Heater Circuit Malfunction Bank 2 Sensor 1

Common Causes of P1155 Toyota

  1. Faulty Sensor: The air/fuel ratio sensor itself may be faulty and require replacement.
  2. Wiring Issues: Damage or corrosion in the wiring harness connected to the sensor can disrupt the heater circuit.
  3. ECM Malfunction: A malfunction in the engine control module (ECM) could prevent the proper operation of the sensor heater.
  4. Poor Electrical Connection: Loose or poor electrical connections to the sensor can cause heater circuit malfunctions.

Symptoms of P1155 Toyota

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the dashboard.
  2. Poor Fuel Economy: A faulty air/fuel ratio sensor can cause the engine to run rich or lean, leading to decreased fuel efficiency.
  3. Rough Idling: The engine may experience rough idling or hesitation due to incorrect air-fuel mixture.
  4. Reduced Engine Performance: The vehicle may lack power or respond sluggishly to throttle input.
  5. Failed Emissions Test: An improperly functioning air/fuel ratio sensor can cause the vehicle to fail emissions testing.

How to Fix P1155 Toyota

  1. Diagnosis: Use a diagnostic tool to confirm the P1155 code and pinpoint the exact cause of the issue.
  2. Sensor Replacement: Replace the air/fuel ratio sensor for bank 2 sensor 1 with a new, OEM-quality part.
  3. Check Wiring: Inspect the wiring harness for any damage or corrosion and repair or replace as needed.
  4. Test ECM: Test the engine control module (ECM) to ensure it is functioning correctly and reprogram if necessary.
  5. Clear Codes: Clear the DTC and reset the check engine light to ensure the repair was successful.

Cost to Fix P1155 Toyota

The cost of repairing a P1155 code for the air/fuel ratio sensor heater circuit malfunction on a Toyota vehicle can vary depending on the specific model and year. On average, the parts cost for a new sensor ranges from $100 to $200, while labor charges can range from $100 to $300. Overall, the total repair cost could fall between $200 and $500. It's important to note that labor rates and part prices may vary based on location and the repair facility. It's recommended to obtain a detailed estimate from a trusted auto repair shop before proceeding with the repair.

When is the Code Detected?

The P1155 is set when the Engine Control Module (ECM) detects a heated oxygen sensor heater circuit malfunction

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Information for Specific Toyota Models

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 P1155 Toyota Code

1. What are the common symptoms of OBDII code P1155 Toyota?

Common symptoms include poor fuel efficiency, rough idling, engine hesitation, and the illumination of the Check Engine Light.

2. What does the OBDII code P1155 Toyota indicate?

This code indicates a malfunction in the air/fuel ratio sensor heater circuit for Bank 2 Sensor 1 in the vehicle's exhaust system.

3. What are the possible causes of the P1155 code in a Toyota vehicle?

Possible causes include a faulty air/fuel ratio sensor, damaged wiring or connectors in the sensor circuit, a blown fuse, or a problem with the engine control module (ECM).

4. How can I diagnose the P1155 code in my Toyota?

Diagnosis typically involves using an OBDII scanner to retrieve the specific fault code, inspecting the sensor and its wiring for damage, and checking the related fuses for continuity.

5. Can I continue driving my vehicle with the P1155 code present?

It is generally not recommended to drive with this code present, as it can lead to decreased fuel efficiency and potential engine performance issues.

6. How can I repair the Air/Fuel Ratio Sensor Heater Circuit Malfunction Bank 2 Sensor 1 code in my Toyota?

Repair options may include replacing the air/fuel ratio sensor, repairing damaged wiring or connectors, replacing blown fuses, or reprogramming the ECM if necessary.

7. Will resetting the Check Engine Light clear the P1155 code?

Resetting the Check Engine Light may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to return after driving the vehicle for a while.

8. How much does it cost to repair the P1155 code in a Toyota?

The cost of repair can vary depending on the specific cause of the code, but it may range from $150 to $500 or more, including parts and labor.

9. Can I replace the air/fuel ratio sensor myself to fix the P1155 code?

Replacing the air/fuel ratio sensor can be a DIY task for those with mechanical experience and the necessary tools. However, if you're unsure, it's best to have a professional technician handle the repair.

10. How often does the P1155 code occur in Toyota vehicles?

The P1155 code related to the air/fuel ratio sensor heater circuit malfunction is a relatively common issue in Toyota vehicles, particularly in older models or those with high mileage.

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