Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer is saying that a part of the car that helps it know how much pollution is coming out is not working right. It's like a thermometer that isn't reading the temperature correctly.
This code indicates that the oxygen sensor heater circuit for the second sensor on the second bank of the engine is experiencing higher than expected voltage.
The oxygen sensor (O2 sensor) measures the amount of oxygen in the exhaust gases. The heater circuit helps the sensor reach the optimal temperature for accurate readings. A high voltage condition in the heater circuit suggests there might be an issue with the wiring, connectors, or the sensor itself.
• Check Engine Light is on
• Poor fuel economy
• Rough idling
• Increased emissions
• Faulty oxygen sensor
• Wiring issues such as shorts or open circuits
• Poor electrical connections
• Faulty PCM (Powertrain Control Module)
O2 Sensor: A device that measures the amount of oxygen in the exhaust gases.
PCM: Powertrain Control Module, the vehicle's onboard computer.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the oxygen sensor heater circuit for proper voltage.
• Check the PCM for faults.
• Replace the faulty oxygen sensor.
• Repair or replace damaged wiring or connectors.
• Ensure proper electrical connections are established.
• Replace the PCM if necessary.
• OBD-II scanner
• Multimeter
• Socket set
$150 - $400
Moderate
• Honda Accord
• Toyota Camry
• Ford F-150
• Regular vehicle maintenance
• Inspect and clean connectors periodically
• Use quality fuel to prevent sensor contamination
Sensor Issue
• Get the vehicle inspected by a professional.
• Avoid driving for long distances until the issue is resolved.
Check vehicle warranty for coverage on emissions-related components.
This code has been associated with vehicles experiencing sensor-related issues due to age or poor maintenance.
Moderate – Should be addressed soon to prevent further issues.
Ignoring this code may lead to increased emissions, which can be illegal in some areas.
• Engine at operating temperature
• Use of a diagnostic scanner
The oxygen sensor is typically located in the exhaust system, after the catalytic converter on the second bank of cylinders.
Q: Can I drive with a P1157 code?
A: It's possible, but not recommended as it can lead to increased emissions and reduced fuel efficiency.
Q: How can I reset the Check Engine Light?
A: Fix the issue causing the code, then use an OBD-II scanner to clear the code.
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Network faults often require full-system access instead of a generic code reader alone.
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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.
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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.
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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.