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 the car's nose isn't working right to smell how clean the air is.
The P0135 code indicates a malfunction in the heater circuit of the oxygen sensor located in Bank 1, Sensor 1. This sensor helps the engine control the air-fuel mixture.
The oxygen sensor in Bank 1, Sensor 1 is responsible for measuring the amount of oxygen in the exhaust gases. It has a built-in heater to quickly reach operating temperature. The P0135 code is triggered when the Engine Control Module (ECM) detects a failure in this heater circuit, meaning the sensor may not be reaching the necessary temperature to provide accurate readings.
• Check Engine Light is on
• Increased fuel consumption
• Poor engine performance
• Failed emissions test
• Blown fuse for the oxygen sensor heater circuit
• Faulty oxygen sensor
• Wiring issues such as open or short circuits
• Poor electrical connections
Oxygen Sensor: A device that measures the proportion of oxygen in the exhaust gases.
Heater Circuit: A component that heats the oxygen sensor to ensure accurate readings.
• Use an OBD-II scanner to verify the P0135 code.
• Inspect the oxygen sensor and its wiring for damage.
• Check the fuse for the oxygen sensor heater circuit.
• Test the oxygen sensor heater circuit for continuity.
• Replace the blown fuse if necessary.
• Repair or replace damaged wiring or connectors.
• Replace the faulty oxygen sensor.
• Clear the code and test drive the vehicle to ensure the issue is resolved.
• OBD-II scanner
• Multimeter
• Socket set
• Wire repair tools
$100 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect and maintain the vehicle's exhaust system.
• Replace oxygen sensors at recommended intervals.
• Ensure proper electrical connections and wiring integrity.
Sensor Issue
• Have a professional inspect and diagnose the issue if you're unsure.
• Avoid ignoring the Check Engine Light as it can lead to further issues.
• Consider regular vehicle maintenance to prevent such issues.
Check with your vehicle manufacturer for warranty coverage on emissions-related components.
The P0135 code has been a common issue in vehicles with older oxygen sensor designs, particularly in models from the late 1990s and early 2000s.
Moderate – While the car may still run, it's important to address this issue to maintain fuel efficiency and emissions standards.
Driving with a malfunctioning oxygen sensor can lead to increased emissions, which may not comply with local environmental regulations.
• Engine at operating temperature
• Vehicle in a safe, stationary position
The oxygen sensor is located in the exhaust manifold or exhaust pipe before the catalytic converter on Bank 1.
Q: Can I drive with a P0135 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: Common signs include a Check Engine Light, poor fuel economy, and rough engine performance.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
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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.