Code Definition

P03B3 — Cylinder 4 Pressure Sensor Circuit

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

About P03B3

P03B3 is a generic (obd-ii standard) powertrain diagnostic trouble code recorded for Honda vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P03B3 is stored, the module has detected 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 P03B3 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 powertrain control module (PCM) monitors the voltage signal from the cylinder 4 in cylinder pressure sensor to verify that combustion pressure tracks the expected values for that cylinder. This sensor, often integrated into the glow plug or a dedicated combustion sensor on diesel applications, feeds the PCM real time pressure data used to optimise injection timing, balance the cylinders, and manage emissions. DTC P03B3 is set when the PCM detects an open, short, or implausible signal outside the predefined voltage thresholds on the cylinder 4 sensor circuit for a sustained period. Common t...

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