Code Definition

P2252 — Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 1 Sensor 1)

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

About P2252

P2252 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 P2252 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 P2252 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 P2252 when it detects a low voltage condition in the reference ground circuit of the air-fuel ratio (A/F) sensor or oxygen (O2) sensor for Bank 1, Sensor 1. This ground circuit is essential for accurate sensor operation. A low voltage condition may indicate an open circuit, high resistance, or a short to ground, leading to incorrect air-fuel mixture readings.

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