AutoCodesSubaru – P0037 Subaru

P0037 Subaru Code - HO2S12 Heater Control Circuit Low

Quick Answer

Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. Common causes include Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2, Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 fuse, Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 harness is open or shorted. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means
P0037 Subaru indicates HO2S12 Heater Control Circuit Low.
Common causes
Common causes include Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2, Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 fuse, Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 harness is open or shorted.
Severity
Moderate - service should be scheduled soon.
Can I drive?
The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 77,686
How popular is this code, among other codes? Medium
Table of contents Created and updated by William Orellana on Mar 23, 2024
💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0037 Subaru Description

Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. The faster the heated oxygen sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM).
In order to achieve the require temperature, a heater element is included inside the heated oxygen sensor. The ECM controls the heated oxygen sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground.
The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.
OBDII Code P0037 Subaru - HO2S12 Heater Control Circuit Low - AutoCodes.com
P0037 Subaru Code - HO2S12 Heater Control Circuit Low

What are the Possible Causes of the DTC P0037 Subaru?

  • Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 fuse
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 harness is open or shorted
  • Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2 circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How to Fix the DTC P0037 Subaru?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0037 Subaru code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0037 Subaru code?

Need more information on how to fix the P0037 Subaru code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0037 Subaru code diagnosed by a professional: Find a repair shop in your area

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0037 Subaru Code

1. What are the common symptoms of OBDII code P0037 on a Subaru related to the HO2S12 heater control circuit low?

The common symptoms include poor fuel economy, rough idling, stalling, and the illumination of the check engine light.

2. What are the potential causes of OBDII code P0037 on a Subaru indicating a HO2S12 heater control circuit low?

Possible causes include a faulty oxygen sensor, damaged wiring, a blown fuse, or a problem with the ECM (engine control module).

3. How can I diagnose the OBDII code P0037 on my Subaru for the HO2S12 heater control circuit low?

To diagnose this code, you can start by checking the oxygen sensor's wiring and connections, testing the sensor's resistance, inspecting the fuse, and scanning the ECM for any related trouble codes.

4. What are the recommended repair tips for resolving OBDII code P0037 on a Subaru due to a HO2S12 heater control circuit low?

Repair tips may include replacing the faulty oxygen sensor, repairing damaged wiring, checking and replacing the fuse if necessary, and clearing the trouble codes with a scan tool.

5. Can driving with OBDII code P0037 related to the HO2S12 heater control circuit low on a Subaru cause any further damage?

Continuing to drive with this code may lead to decreased fuel efficiency and potential damage to the catalytic converter over time, so it is recommended to address the issue promptly.

6. How much does it typically cost to repair OBDII code P0037 on a Subaru caused by a HO2S12 heater control circuit low?

The cost of repair can vary depending on the root cause of the issue, but it may range from $100 to $300 for parts and labor.

7. Is it safe to drive my Subaru with the check engine light on due to OBDII code P0037 indicating a HO2S12 heater control circuit low?

While it may be safe to drive in the short term, it is advisable to address the issue promptly to prevent potential long-term damage and ensure optimal vehicle performance.

8. How long does it usually take to repair OBDII code P0037 on a Subaru related to the HO2S12 heater control circuit low?

The repair time can vary depending on the exact cause of the code and the availability of parts, but it typically takes around 1-2 hours for a professional technician to diagnose and fix the issue.

9. Can I reset the check engine light myself after resolving OBDII code P0037 on my Subaru caused by a HO2S12 heater control circuit low?

Yes, you can typically reset the check engine light by using an OBDII scanner or disconnecting the car's battery for a few minutes. If the issue is resolved, the light should reset.

10. Will OBDII code P0037 on a Subaru for the HO2S12 heater control circuit low pass during an emissions test once repaired?

After resolving the issue and resetting the check engine light, the code should not reappear during an emissions test, assuming the repair was successful and the vehicle's emissions system is functioning properly.

Discuss the causes and fixes for P0037 Subaru OBDII Code

Code P0037 Subaru comments

No comments found for this page.

AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play