Code Definition

P242B — Exhaust Gas Temperature Sensor Circuit Range/Performance Bank 1 Sensor 3

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

About P242B

P242B 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 P242B 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.

Because P242B 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 monitors exhaust gas temperature sensor 3 on bank 1 to protect and manage the diesel particulate filter and to control exhaust emissions. DTC P242B sets when the signal from this EGT sensor is present but implausible, meaning it falls outside the expected range or does not track exhaust temperature the way the ECM predicts from engine load, the other EGT sensors, and operating conditions. This downstream sensor lets the ECM confirm safe DPF regeneration temperatures and detect exhaust overheating. When the code is set the ECM may disable or limit DPF regeneration, ill...

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