P0037
Fix within 1-2 weeksYour engine computer detected a problem with the heater circuit for the downstream oxygen sensor on Bank 1. This sensor is located after the catalytic converter and helps monitor its efficiency.
Code P0037 means your downstream oxygen sensor's heater circuit has low voltage. Common causes: Failed O2 sensor (80%), wiring issues (15%), blown fuse (4%). Drivability: Yes, safe to drive. Repair cost: $40-$150 DIY, $140-$450 professional.
Can I Drive With P0037?
Yes, safe to drive
No restrictions
Stop driving immediately if: Flashing Check Engine Light (indicates a misfire), loud exhaust noises, burning smell, significant power loss.
Symptoms of P0037
- 1Check Engine Light is on
- 2Slight decrease in fuel economy
- 3Vehicle may fail an emissions test
Common Causes of P0037
Parts most likely causing this code, ranked by probability
The heater element inside the oxygen sensor has failed, preventing it from reaching operating temperature quickly.
80% of P0037 cases are fixed by replacing this part
Damaged, corroded, or loose wiring in the oxygen sensor's heater circuit prevents proper voltage delivery.
15% of P0037 cases are fixed by repairing wiring
A blown fuse in the oxygen sensor heater circuit cuts off power to the sensor's heating element.
4% of P0037 cases are fixed by replacing a fuse
A rare internal fault within the engine computer can cause it to incorrectly report a low heater circuit voltage.
1% of P0037 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Visually inspect the Bank 1 Sensor 2 oxygen sensor and its wiring for any cuts, burns, or corrosion.
- Check the fuse box for a blown fuse related to the oxygen sensor heater circuit.
How to Diagnose P0037
- 1Visually inspect the Bank 1 Sensor 2 oxygen sensor and its wiring for any obvious damage, fraying, or corrosion.
- 2Locate and check the fuse for the oxygen sensor heater circuit (refer to your vehicle's owner's manual or service information).
- 3Using a multimeter, check for proper voltage at the oxygen sensor connector for the heater circuit wires (usually two wires).
- 4Disconnect the oxygen sensor and measure the resistance of the heater element across the two heater pins on the sensor itself. Compare to factory specifications.
P0037 on Popular Vehicles
Toyota Camry
2007-2024Downstream O2 sensor heater failure is a frequent occurrence. The sensor is typically accessible under the vehicle.
85% fixed by replacing the O2 sensor
Honda Accord
2003-2024Similar to Toyota, Honda Accords often experience P0037 due to the downstream O2 sensor heater failing. Check for exhaust leaks near the sensor as well.
80% fixed by replacing the O2 sensor
Ford F-150
2004-2024On F-150s, P0037 can be caused by the O2 sensor itself or by wiring damage due to road debris or exhaust heat. Always inspect wiring thoroughly.
75% fixed by replacing the O2 sensor
Frequently Asked Questions
What does P0037 mean?
P0037 indicates that your vehicle's engine computer has detected a low voltage condition in the heater circuit of the Bank 1 Sensor 2 oxygen sensor. This sensor is located after the catalytic converter and its heater helps it reach operating temperature quickly for accurate readings.
Can I drive with P0037?
Yes, you can drive safely with a P0037 code. This code typically does not cause immediate drivability issues or engine damage. However, your fuel economy may decrease slightly, and your vehicle will fail an emissions test.
Will P0037 clear itself?
No, P0037 will not clear itself. The engine computer will continue to detect the fault in the oxygen sensor heater circuit. You need to diagnose and fix the underlying problem, then clear the code with an OBD-II scanner.
How do I fix P0037 myself?
Start by visually inspecting the oxygen sensor and its wiring for damage. Check the relevant fuse. If those are good, test the voltage at the sensor connector and the resistance of the sensor's heater element. Most often, replacing the Bank 1 Sensor 2 oxygen sensor resolves this code.
How much does it cost to fix P0037?
The cost to fix P0037 yourself is typically $40-$150 for a new oxygen sensor. If you take it to a professional shop, expect to pay $140-$450, which includes parts and 0.5-1.5 hours of labor.
P0037 keeps coming back - why?
If P0037 keeps returning, it means the underlying issue was not fully resolved. This often happens if you only replaced the sensor but had a wiring problem, a blown fuse that keeps blowing, or a rare ECM fault. Thoroughly re-check the wiring, connector, and fuse before considering an ECM issue.
Will P0037 fail emissions/smog test?
Yes, P0037 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on is an automatic failure in most states, and the faulty oxygen sensor heater circuit means the emissions system is not operating as designed.
What's the difference between P0037 and P0038?
P0037 indicates a 'Heater Control Circuit Low' for the Bank 1 Sensor 2 oxygen sensor, meaning the voltage is too low. P0038 indicates a 'Heater Control Circuit High' for the same sensor, meaning the voltage is too high. Both point to an issue with the sensor's heater circuit, but in opposite directions.
P0037 on Toyota Camry?
P0037 is a common code on Toyota Camry models, especially those with higher mileage. The downstream oxygen sensor heater element is a known failure point. Replacing the Bank 1 Sensor 2 oxygen sensor is a very common and effective fix for this code on a Camry.
Questions to Ask Your Mechanic
Did you check the fuse for the O2 sensor heater circuit?
Good answer: Yes, I confirmed the fuse is good and receiving power from the relay.
What voltage did you measure at the O2 sensor connector's heater circuit?
Good answer: I measured [X] volts, which is below the specified range, indicating a wiring or sensor issue.
What was the resistance reading of the O2 sensor's heater element?
Good answer: The heater element showed an open circuit (infinite resistance) or a reading outside the factory specification, confirming an internal sensor failure.
Repair Cost Estimate
DIY Repair
Parts only
$40-$150
Shop Repair
Parts + labor
$140-$450
Save $100-$300 by doing it yourself
Difficulty
beginner
Time
0.5-1.5 hours
Beginner-friendly - The downstream oxygen sensor is typically easy to access, and the repair requires basic hand tools and a multimeter.
Cost of Waiting
Ignoring P0037 will not cause immediate engine damage. However, your vehicle will consume more fuel than necessary, costing you money at the pump. It will also fail any required emissions testing. Over a very long period, incorrect fuel trim adjustments from a faulty downstream sensor could indirectly impact catalytic converter life, but this is less direct than an upstream sensor issue.
While You're In There...
If the O2 sensor is difficult to remove or requires disturbing exhaust components, replacing a nearby exhaust gasket prevents future leaks and repeat labor.
Applying anti-seize to the new O2 sensor threads prevents it from seizing in the exhaust pipe, making future removal much easier.
Tools You'll Need
- OBD-II scanner
- Multimeter
- Ratchet and socket set
- Oxygen sensor socket (7/8 inch or 22mm)
- Wire brush (for cleaning threads)
P0037 is a very common code, and the fix is usually straightforward. Most repairs involve replacing an accessible part, and your vehicle will return to normal fuel economy and emissions performance.
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Your Next Steps
Step 1: Perform a thorough visual inspection of the Bank 1 Sensor 2 oxygen sensor and its wiring. Look for any signs of damage, chafing, or corrosion on the connector.
Step 2: Locate and check the fuse for the oxygen sensor heater circuit. Replace it if blown. If the fuse blows again, you have a short in the wiring or the sensor itself.
Step 3: If the fuse is good and wiring looks okay, use a multimeter to test for voltage at the sensor connector and measure the resistance of the heater element on the sensor. If the sensor's heater resistance is out of specification, replace the Bank 1 Sensor 2 oxygen sensor.