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P0037 Fault Code (Causes & Fixes) HO2S Heater Control Circuit Low (Bank 1, Sensor 2)

Updated: Feb 4

✔ This article has been fact checked.

When the Engine Control Module (ECM) detects a signal voltage from oxygen sensor 2 that is not within the specified range, the "HO2S Heater Control Circuit Low (Bank 1, Sensor 2)" OBD code P0037 is generated.

If a DTC is associated to the powertrain, an OBD scanner will read it as starting with P, thus the letter "P". Generic fault codes are those of the format P0xxx.

Table of Contents:

The Meaning of a P0037 Fault Code

The P0037 error code means that the heated oxygen sensor (HO2S) control circuit bank 1, sensor 2 is not sending the correct data to the powertrain control module (PCM).

For the engine to run effectively, the engine should have a perfect air-fuel ratio of 14.7 to 1, and the HO2S (oxygen sensor) analyses the oxygen content from the exhaust to ensure this air-fuel ratio is met.

It's heated to ensure the PCM responds quickly to the closed-loop system, minimising emissions at startup.

The fault code P0037 appears when there is a problem with the HO2S heating element, in this case a too low voltage.

Is It Serious?

This diagnostic code is considered minor-to-moderate. Because the HO2S is such a minimal role in how a vehicle functions, there are usually relatively few driveability symptoms.

As a consequence, the vehicle may be driven, but it should be taken in for diagnostic and repair as soon as possible to prevent future problems such as the ones listed below.

  • poor performance