Code Definition

P102D — O2 Sensor Heater Circuit Performance Bank 1 Sensor 2 Stuck ON

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Toyota

About P102D

P102D is a manufacturer-specific 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 P102D is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour; 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.

P102D is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

DTC P102D is a performance code for the oxygen sensor heater on Bank 1 Sensor 2, the downstream sensor after the catalytic converter, and the Stuck ON description means the ECM sees the heater circuit staying energised or drawing current when it should be switched off. The ECM normally pulse width modulates the heater to bring the sensor to operating temperature and then reduces it, monitoring current and circuit voltage as it does. P102D sets when that current does not stop as commanded, which usually points to a short to voltage in the wiring, a heater or connector fault, or, less often, an ...

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