Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car has a sensor that checks how clean the exhaust is. This sensor needs to be warm to work properly, and there's a heater to keep it warm. This code means the heater isn't working well.
The P0037 code indicates that the heater circuit for the oxygen sensor located in Bank 1, Sensor 2 is not functioning properly, showing a low voltage condition.
The Heated Oxygen Sensor (HO2S) is used to monitor the amount of oxygen in the exhaust gases. The sensor has a built-in heater to help it reach its operating temperature quickly. The P0037 code is triggered when the Engine Control Module (ECM) detects a low voltage in the heater circuit of the downstream oxygen sensor (Bank 1, Sensor 2).
• Check Engine Light is on
• Increased emissions
• Poor fuel economy
• Rough engine idle
• Faulty oxygen sensor heater
• Blown fuse for the heater circuit
• Wiring issues such as open or short circuits
• Faulty ECM
ECM: Engine Control Module, the computer that controls engine functions.
HO2S: Heated Oxygen Sensor, a sensor that measures oxygen levels in the exhaust.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage.
• Check the fuse for the oxygen sensor heater circuit.
• Test the oxygen sensor heater resistance.
• Replace the faulty oxygen sensor.
• Repair or replace damaged wiring or connectors.
• Replace the blown fuse.
• Test and replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$100 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly inspect and maintain the exhaust system.
• Ensure timely replacement of oxygen sensors.
• Check electrical connections periodically.
Sensor Issue
• Avoid ignoring the Check Engine Light.
• Consult a mechanic if unsure about repairs.
Check your vehicle's warranty for coverage on emissions-related components.
This code has been common in vehicles with aging oxygen sensors or poor electrical connections.
Moderate – While not immediately critical, it should be addressed to avoid increased emissions and potential damage to the catalytic converter.
Driving with a malfunctioning oxygen sensor can lead to increased emissions, which may not comply with environmental regulations.
• Engine at operating temperature
• Vehicle in closed-loop mode
The Bank 1 Sensor 2 oxygen sensor is located on the exhaust system behind the catalytic converter on the side of the engine with cylinder 1.
Q: Can I drive with a P0037 code?
A: While the car may still run, it's best to fix the issue to avoid increased emissions and fuel consumption.
Q: How can I prevent this code from appearing?
A: Regular maintenance and inspections of the exhaust and sensor systems can help prevent this issue.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
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.
View on Amazon
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.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.
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.
View options on Amazon
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.