P242D — Exhaust gas temperature sensor circuit high, bank 1, sensor 3

The controller reports an electrical input above the calibrated threshold in the specified exhaust-gas temperature sensor circuit. A high electrical signal is not necessarily a high physical exhaust temperature and does not identify a failed sensor by itself. Interpret voltage and live data using the manufacturer wiring diagram and specifications. This code identifies bank 1, sensor 3; sensor numbering can differ from the physical order on a specific vehicle.

Affected system: Exhaust gas temperature monitoring

Symptoms

• A check-engine or emissions-system warning may appear.
• Reduced engine power may occur on some vehicles, although there may be no obvious driving symptoms.

Possible causes

• An exhaust-gas temperature sensor fault at bank 1, sensor 3, may produce a high electrical circuit signal.
• Open or shorted wiring, especially where the harness is exposed to exhaust heat, can affect the signal.
• Damaged, loose, or corroded sensor connector terminals may disrupt the circuit.

What to check

• Read accompanying fault codes; do not interpret a high circuit signal as proof of excessively hot exhaust.
• With the exhaust cold, inspect the bank 1 sensor 3 wiring and connector for heat damage or corrosion.
• Check circuit continuity and supply or signal voltage against the vehicle's service specifications.
• Where supported, compare the sensor's resistance or response with the manufacturer data.
• Investigate the engine control module only after the sensor and its circuit have been assessed.

Also written as: P242D-00, P242D00 (some scan tools add the fault-type byte, e.g. -00).