Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the part of your car that helps the engine know how much fuel to use. It's like a tiny heater isn't working right.
The P0155 code indicates that the heater circuit in the oxygen sensor located at Bank 2 Sensor 1 is not functioning properly.
Oxygen sensors are equipped with a heater to help them reach operating temperature quickly. The P0155 code is set when the Engine Control Module (ECM) detects that the heater circuit of the oxygen sensor in Bank 2 Sensor 1 is not working as expected. This can affect the sensor's ability to accurately measure the oxygen levels in the exhaust gases, leading to inefficient fuel combustion.
• Check Engine Light is on
• Increased fuel consumption
• Rough engine idle
• Failed oxygen sensor
• Blown fuse for the oxygen sensor heater circuit
• Damaged wiring or connectors in the oxygen sensor circuit
Oxygen Sensor: A device that measures the amount of oxygen in the exhaust gases.
Bank 2: The side of the engine opposite to Bank 1, usually the side without cylinder 1.
Heater Circuit: A component in the oxygen sensor that helps it reach operating temperature quickly.
• Use an OBD-II scanner to confirm the code.
• Check the fuse for the oxygen sensor heater circuit.
• Inspect the wiring and connectors for damage or corrosion.
• Replace the oxygen sensor.
• Repair or replace damaged wiring or connectors.
• Replace the blown fuse.
• OBD-II scanner
• Multimeter
• Socket set
$150 - $300
Moderate
• Toyota Camry
• Ford F-150
• Honda Accord
• Regularly inspect and maintain the exhaust system.
• Replace oxygen sensors at recommended intervals.
• Ensure electrical connections are clean and secure.
Sensor Issue
• Have the vehicle inspected by a professional mechanic.
• Avoid prolonged driving with the Check Engine Light on to prevent further damage.
Check with your vehicle manufacturer for specific warranty coverage on emissions-related components.
The P0155 code has been a common issue in vehicles with aging oxygen sensors, often appearing after 60,000 miles.
Moderate – While the car may still run, it can lead to poor fuel economy and potential damage to the catalytic converter.
Driving with a malfunctioning oxygen sensor can lead to increased emissions, which may not comply with local environmental regulations.
• Engine must be at operating temperature.
• Vehicle should be driven under normal conditions.
The oxygen sensor for Bank 2 Sensor 1 is located on the exhaust manifold of the engine's second bank.
Q: Can I drive my car with a P0155 code?
A: Yes, but it is not recommended to drive for an extended period as it can lead to increased fuel consumption and potential damage to the catalytic converter.
Q: How do I know if my oxygen sensor is bad?
A: Symptoms include a Check Engine Light, poor fuel economy, and rough idle. An OBD-II scanner can confirm the issue.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.
Fitment Required · Vehicle-fitment part
Relevant when the code or supporting diagnostics point toward upstream or downstream oxygen-sensor faults.
This code family often involves upstream or downstream oxygen-sensor diagnosis.
Verify exact sensor position and vehicle fitment before buying.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.