P242A - CATALYST TEMPERATURE SENSOR CIRCUIT BANK 1 SENSOR 2

The Exhaust Gas Temperature (EGT) sensor protects the catalytic converter (TWC) from high temperatures. It turns the temperature into a voltage signal via an internal heat-sensitive resistor. This signal is sent to the Powertrain Control Module (PCM). On the other hand, in vehicles with diesel engines, this sensor determines the DEF (Diesel Exhaust Fluid) injection timing as temperatures rise. The resistance of the sensor varies according to the exhaust temperature, the higher the temperature, the lower the resistance voltage will be. In contrast, when the temperature is low, the voltage level will increase.

The fault code P242A OBDII is stored when the PCM detects a general malfunction in the EGT sensor circuit. This code may be accompanied by another code referring to the sensor.

• Check Engine light ON.

Reasons for setting the P242A OBD2 diagnostic code:

• Excessive soot accumulation in the EGT Sensor.
• EGT Sensor cables or connectors may be faulty.
• The cat-back exhaust system may not have the Exhaust Gas Temperature provisions added.

To troubleshoot the DTC P242A OBDII code, try this.

• Consult the Technical Service Bulletins (TSB).
• Check the wires and connectors of the Exhaust Gas Temperature Sensor for bank 1 carefully. If you notice these components are causing the circuit to fail, make repairs as required.
• Verify there is no accumulation of elements around the Exhaust Gas Temperature Sensor that alter its functions. Perform maintenance if you observe these elements.
• Use a Digital Volt-Ohm Meter to perform resistance tests on the EGT Sensor. If you find that the resistance reading differs from the manufacturer's data, check for good electrical connections. If necessary, replace the sensor.