Code Definition

P2237 — Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)

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

About P2237

P2237 is a generic (obd-ii standard) powertrain diagnostic trouble code recorded for Toyota vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P2237 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit; 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 P2237 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

The engine control module (ECM) sets P2237 when it detects an open circuit or improper current flow in the air-fuel ratio (A/F) sensor pumping circuit for Bank 1, Sensor 1. The A/F sensor relies on a controlled pumping current to measure oxygen levels accurately. If the ECM detects that the expected current is not present, it triggers this fault, which can lead to incorrect fuel trim adjustments.

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