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 controlling the heater for one of the oxygen sensors. It's like when a heater in your house isn't working right, so the room doesn't get warm enough.
The P1187 code indicates an issue with the heater control circuit of the oxygen sensor located on bank 2, sensor 2. This sensor helps the car's computer monitor and adjust the fuel mixture for optimal performance.
The oxygen sensor heater is responsible for bringing the sensor up to operating temperature quickly to ensure accurate readings. Bank 2 refers to the side of the engine with the second cylinder in a V-type engine. Sensor 2 is the downstream sensor, which monitors the efficiency of the catalytic converter. A malfunction in the heater circuit can lead to delayed sensor operation and inaccurate fuel mixture adjustments.
• Check Engine Light illuminated
• Poor fuel economy
• Failed emissions test
• Faulty oxygen sensor
• Damaged wiring or connectors
• Blown fuse for the sensor heater circuit
Oxygen Sensor: A device that measures the amount of oxygen in the exhaust gases.
Heater Circuit: An electrical circuit that heats the oxygen sensor to ensure it operates efficiently.
• Use an OBD-II scanner to confirm the code
• Inspect the wiring and connectors for damage
• Test the oxygen sensor heater circuit for continuity
• Replace the faulty oxygen sensor
• Repair or replace damaged wiring
• Replace blown fuse
• OBD-II scanner
• Multimeter
• Socket set
$150 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect and maintain oxygen sensors
• Ensure wiring harnesses are secure and undamaged
• Use high-quality fuel to prevent sensor contamination
Sensor Issue
• Have the vehicle inspected by a professional if you are unsure
• Avoid driving long distances until the issue is resolved
Check with your vehicle manufacturer for specific warranty coverage related to emissions components.
Oxygen sensor heater circuit issues have been common as vehicles rely more on precise emissions control.
Moderate – While the vehicle is still drivable, prolonged use can lead to increased emissions 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 operation
The oxygen sensor is located in the exhaust system, downstream of the catalytic converter on bank 2.
Q: Can I drive with a P1187 code?
A: While you can drive with this code, it's best to fix it soon to avoid increased emissions and potential damage.
Q: How do I know if my oxygen sensor is bad?
A: Symptoms include poor fuel economy, a rough idle, and an illuminated check engine light.
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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.