Code Definition

P0037 — Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 2

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0037

P0037 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0037 is stored, the module has detected a signal or supply voltage lower than the expected operating range; a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0037 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

DTC P0037 indicates a low voltage condition in the heater control circuit of the downstream oxygen sensor on Bank 1 Sensor 2, the sensor mounted after the catalytic converter. That sensor has an internal heater that quickly brings it up to operating temperature after start up so it can give accurate readings for catalyst monitoring, and the ECM switches the heater on the ground side while monitoring the circuit. P0037 sets when the ECM detects the heater control voltage is lower than expected, usually meaning the circuit is pulling low through a short to ground, or the heater or its feed is fa...

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