Code Definition

P042C — Catalyst temperature sensor circuit low bank 1 sensor 2

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

About P042C

P042C 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 P042C 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 P042C 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 P042C fault code is set when the Engine Control Module (ECM) detects a lower than expected voltage in the circuit of the catalyst temperature sensor for Bank 1, Sensor 2. This low voltage condition suggests an issue in the electrical circuit connected to the sensor, which is responsible for monitoring the temperature of the exhaust gases passing through the catalytic converter in Bank 1. Accurate temperature measurement by this sensor is crucial for efficient emission control and to prevent overheating or damage to the catalytic converter. A low voltage in the circuit can lead to incorrect...

Join TaT to view the complete code information and diagnostic details.

Quick Facts