Code Definition

P042B — Catalyst temperature sensor circuit malfunction bank 1 sensor 2

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

About P042B

P042B 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 P042B is stored, the module has detected 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 P042B 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 P042B fault code is set when the Engine Control Module (ECM) detects a malfunction within the circuitry of the catalyst temperature sensor for Bank 1, Sensor 2. This code indicates an issue affecting the electrical circuit connected to the sensor, which monitors the temperature of the exhaust gases in the catalytic converter of Bank 1. The proper functioning of this sensor is crucial for regulating the catalytic converter's temperature, ensuring effective emission control and preventing damage to the converter. A circuit malfunction can lead to inaccurate temperature readings and potential...

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