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 getting a low signal from the oxygen sensor in the exhaust system on the side of the engine that has the second set of cylinders. This sensor helps the car know how much fuel to use.
The P0157 code is triggered when the oxygen sensor located on bank 2, sensor 2, sends a low voltage signal to the engine control module (ECM) for a specific duration.
Oxygen sensors measure the amount of oxygen in the exhaust gases leaving the engine. Bank 2 refers to the side of the engine opposite to cylinder 1. Sensor 2 is located after the catalytic converter. A low voltage signal indicates that the sensor is reading a lean mixture, meaning too much air and not enough fuel in the exhaust.
• Check Engine Light is on
• Poor fuel economy
• Rough engine idle
• Increased emissions
• Faulty oxygen sensor
• Exhaust leak near the sensor
• Wiring issues or poor electrical connection
• Faulty ECM
ECM: Engine Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connections to the oxygen sensor.
• Check for exhaust leaks near the sensor.
• Test the oxygen sensor with a multimeter.
• Repair or replace faulty wiring or connectors.
• Replace the oxygen sensor if faulty.
• Repair any exhaust leaks.
• Update or reprogram the ECM if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $300
Moderate
• Toyota Camry
• Ford F-150
• Chevrolet Silverado
• Regular maintenance and inspection of the exhaust system.
• Ensure proper fuel quality.
• Regularly check and clean electrical connections.
Sensor Issue
• Avoid driving with a persistent check engine light.
• Get regular vehicle check-ups to prevent sensor issues.
Oxygen sensors may be covered under the vehicle's emissions warranty.
This code has been commonly associated with sensor degradation over time, especially in high-mileage vehicles.
Moderate – Addressing this issue will improve fuel efficiency and emissions.
Driving with a faulty oxygen sensor can lead to increased emissions, which may not comply with local environmental regulations.
• Engine at operating temperature
• Vehicle running at idle
The oxygen sensor is located on the exhaust pipe after the catalytic converter on the side of the engine opposite cylinder 1.
Q: Can I drive with a P0157 code?
A: While you can drive with this code, it's not recommended as it can lead to poor fuel economy and increased emissions.
Q: How do I know if my oxygen sensor is bad?
A: Symptoms of a bad oxygen sensor include a check engine light, poor fuel economy, and rough idling.
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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.