P0155 Code - O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1
Quick Answer
Heated Oxygen Sensors (HO2S) are used for fuel control and post catalyst monitoring. Common causes include Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1, Heated Oxygen Sensor Bank 2 Sensor 1 harness is open shorted, Heated Oxygen Sensor Bank 2 Sensor 1 circuit poor electrical connection. 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 indicates O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1.
- Common causes
- Common causes include Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1, Heated Oxygen Sensor Bank 2 Sensor 1 harness is open shorted, Heated Oxygen Sensor Bank 2 Sensor 1 circuit poor electrical connection.
- 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.
Code P0155 Description
The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the HO2S 1 heater current is out of factory specifications.
What are the Possible Causes of the DTC P0155?
- Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1
- Heated Oxygen Sensor Bank 2 Sensor 1 harness is open shorted
- Heated Oxygen Sensor Bank 2 Sensor 1 circuit poor electrical connection
- Heated Oxygen Sensor Bank 2 Sensor 1 circuit fuse
- Faulty Engine Control Module (ECM)
How to Fix the DTC P0155?
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.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0155 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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Information for Specific Makes
- P0155 Acura — A/F Sensor 21 Heater System Malfunction
- P0155 Audi — HO2S21 Sensor Heater Circuit
- P0155 BMW — O2 Sensor Heater Circuit Bank 2 Sensor 1
- P0155 Buick — HO2S Heater Performance Bank 2 Sensor 1
- P0155 Cadillac — HO2S Heater Performance Bank 2 Sensor 1
- P0155 Chevrolet — HO2S Heater Performance Bank 2 Sensor 1
- P0155 Chrysler — O2 Sensor 2/1 Heater Performance
- P0155 Dodge — O2 Sensor 2/1 Heater Performance
- P0155 Ford — O2 Heater Circuit Bank 2 Sensor 1
- P0155 GMC — HO2S Heater Performance Bank 2 Sensor 1
- P0155 Honda — A/F Sensor 21 Heater System Malfunction
- P0155 Hyundai — HO2S Heater Circuit Bank 2 Sensor 1
- P0155 Infiniti — O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1
- P0155 Jeep — O2 Sensor 2/1 Heater Performance
- P0155 KIA — HO2S21 Heater Circuit
- P0155 Lexus — O2 Sensor Heater Circuit Bank 2 Sensor 1
- P0155 Mazda — HO2S21 Heater Circuit Fault
- P0155 Mercedes-Benz — O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1
- P0155 MINI — O2 Sensor Heater Circuit Bank 2 Sensor 1
- P0155 Mitsubishi — HO2S 21 Heater Performance
- P0155 Nissan — O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 1
- P0155 Pontiac — HO2S Heater Performance Bank 2 Sensor 1
- P0155 Saturn — HO2S Heater Performance Bank 2 Sensor 1
- P0155 Toyota — O2 Sensor Heater Circuit Bank 2 Sensor 1
- P0155 Volkswagen — HO2S21 Sensor Heater Circuit
Frequently Asked Questions about P0155 Code
What does the OBDII code P0155 mean?
P0155 indicates a malfunction in the heater circuit for the oxygen sensor located in Bank 2, Sensor 1, meaning the sensor’s heater element is not warming up as expected.
What are the symptoms of a P0155 code?
Common symptoms include an illuminated check engine light, increased fuel consumption, and possible rough idling or poor engine performance.
What causes a P0155 code?
Possible causes include a faulty oxygen sensor, damaged wiring or connectors, a blown fuse, or issues with the engine control module (ECM).
Can I drive with a P0155 code?
While the vehicle might still be drivable, prolonged driving with a P0155 code can lead to reduced fuel efficiency and potential damage to the catalytic converter.
How can I fix a P0155 code?
First, inspect and repair any damaged wiring or connectors. If the issue persists, replacing the oxygen sensor in Bank 2, Sensor 1, is often necessary.
How do I locate Bank 2 Sensor 1?
Bank 2 refers to the side of the engine opposite Bank 1 (the side with cylinder 1), and Sensor 1 is the upstream sensor located before the catalytic converter.
Can a bad fuse cause a P0155 code?
Yes, a blown fuse in the oxygen sensor heater circuit can prevent the sensor from functioning properly and trigger the P0155 code.
Do I need special tools to diagnose a P0155 code?
A basic OBDII scanner can detect the code, but a multimeter or advanced diagnostic tools may be needed to check the wiring and sensor heater resistance.
How much does it cost to fix a P0155 code?
Repair costs vary but typically range from $150 to $400, depending on whether you need to replace the oxygen sensor or address wiring issues.
What happens if I ignore a P0155 code?
Ignoring a P0155 code can lead to decreased fuel efficiency, increased emissions, and potential damage to the catalytic converter over time.
Discuss the causes and fixes for P0155 OBDII Code
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