P0037 – Meaning, Causes, Symptoms, & Fixes

Code P0037 Definition

H02S Heater Control Circuit Low (Bank 1, Sensor 2)

What Does P0037 Mean?

The HO2S (heated oxygen) sensor calculates the oxygen ratio of the vehicle’s exhaust. This ratio is then communicated to the ECM which controls the emissions of the vehicle. The P0037 code is set when the ECM detects the HO2S sensor is malfunctioning and sending faulty information. In rare cases, the ECM can be defective.

P0037 Symptoms

P0037 Causes

  • Faulty oxygen sensor (bank 1)
  • Shorted wiring in Control circuit
  • Malfunctioning ECM sensor heater driver
  • Shorted battery connector
  • Faulty ECM

Code P0037 Severity – Low

This trouble code will not prevent your vehicle from operating, but may cause it to fail emissions tests. The most common error(s) include: lowered fuel economy, rough engine performance, and HO2S sensor errors. It is recommended to have this code fixed to prevent further damage to the vehicle.

Code P0037 Common Diagnosis Mistakes

Prematurely replacing the HO2S (heated oxygen) sensor without visually inspecting the wiring of the control circuit for disconnection.

P0037 Diagnosis

  • Tools Needed to Diagnose:

Difficulty of Diagnosis and Repair

  1. Check to see if there are any other codes along with P0037 and clear your Check Engine Light with FIXD.
  2. Check the freeze frame data in an attempt to pinpoint the issue.
  3. Visually inspect the wiring around the control circuit sensor for disconnection.
  4. If the wiring directly attached to the HO2S sensor is damaged, replace the HO2S sensor.
  5. Check resistance of heater element to ensure it is within specified range.
  6. If no voltage is detected (open circuit), replace any blown fuse from the short.
  7. If the problem persists, consider replacing the HO2S sensor.

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Comments 3


April 2, 2019

Turns out it was a blown fuse… after we changed the O2 sensor


June 10, 2019

Will this problem cause the vsc trac off light to come on?


July 10, 2019

Found loose connection ; passenger side , under carpet, left side, where the O2 sensor enters the cabin

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