Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is having trouble with one of the oxygen sensors. It's like when your game controller isn't getting enough power, so it doesn't work right.
The P1156 code indicates a problem with the heater circuit of the oxygen sensor located in Bank 2, Sensor 2. The sensor is not receiving enough voltage to operate properly.
Oxygen sensors monitor the oxygen levels in the exhaust gases. The heater circuit helps the sensor reach its operating temperature quickly. When the voltage in the heater circuit is too low, the sensor may not function correctly, leading to inefficient engine performance and increased emissions.
• Check Engine Light is on
• Poor fuel economy
• Failed emissions test
• Faulty oxygen sensor
• Blown fuse for the heater circuit
• Wiring issues such as a short or open circuit
Bank 2: The side of the engine opposite to Bank 1, usually the side without cylinder 1.
Sensor 2: Refers to the downstream sensor located after the catalytic converter.
• Use an OBD-II scanner to confirm the code.
• Inspect the oxygen sensor and its wiring for damage.
• Check the fuse for the heater circuit.
• Replace the faulty oxygen sensor.
• Repair or replace damaged wiring.
• Replace the blown fuse.
• OBD-II scanner
• Multimeter
• Socket set
$100 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect and maintain the exhaust system.
• Ensure proper electrical connections.
• Replace oxygen sensors at recommended intervals.
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if unsure.
• Regular maintenance can prevent such issues.
Oxygen sensors may be covered under emissions warranty depending on the vehicle's age and mileage.
Oxygen sensor issues have been common as vehicles rely more on electronic sensors for efficient operation.
Moderate – Should be addressed soon to avoid poor fuel economy and potential damage to the catalytic converter.
Driving with a faulty oxygen sensor can lead to increased emissions, which may not comply with local environmental regulations.
• Engine at operating temperature
• Vehicle in closed-loop mode
The oxygen sensor is located in the exhaust system, typically after the catalytic converter on Bank 2.
Q: What is an oxygen sensor?
A: An oxygen sensor measures the amount of oxygen in the exhaust gases to help the engine run efficiently.
Q: Can I drive with a P1156 code?
A: It's possible to drive, but it's not recommended as it can lead to poor fuel economy and increased emissions.
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Specialty · Smoke machine
Helpful for finding EVAP and vacuum leaks that are hard to see with visual inspection alone.
Helpful for tracking down EVAP and vacuum leaks that can trigger emissions faults.
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Specialty · O2 sensor socket
Helpful when the code points toward exhaust or oxygen-sensor work and space is tight.
Useful when the diagnosis points toward oxygen-sensor removal or replacement.
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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.
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Fitment Required · Vehicle-fitment part
Relevant when catalyst-efficiency or emissions faults persist after proper diagnosis.
Catalyst-efficiency faults sometimes point toward converter problems after proper testing.
Catalytic converters are highly vehicle-specific and should not be purchased by code alone.
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.