P0544 - EXHAUST GAS RECIRCULATION TEMPERATURE (EGRT) SENSOR, BANK 1 - CIRCUIT MALFUNCTION

The OBDII fault code P0544 shows a malfunction in the Exhaust Gas Temperature (EGT) sensor circuit. This sensor protects the Catalytic Converter (TWC) from heat damage.

This sensor is a heat-sensitive resistor. It turns the exhaust temperature into a voltage signal. Then, it sends it to the vehicle’s computer. It has 5 volts of reference, which the computer sends by itself.

When the exhaust temperature is high, the resistance to the ground decreases. But if the temperature level is low, the resistance increases, and there is low voltage. If low voltage is found in the engine, the PCM (Powertrain Control Module) changes the engine timing or fuel ratio to keep the temperature in a range suitable for the TWC.

If the EGT Sensor voltage readings are greater than the limit set by the manufacturer, this code will be set and the Check Engine light will light up.

• MIL (Motor Malfunction) light ON.

The reasons why the P0544 OBD2 diagnostic code is set are:

• Some cables, connectors, or terminals may be poorly fitted or corroded.
• Perhaps the Exhaust Gas Temperature (EGT) sensor is shorted internally.
• The EGT sensor may be faulty.
• Leaks in the exhaust system.

The steps to troubleshoot faults related to DTC P0544 OBDII are as follows:

• Check all the wires leading to the Exhaust Gas Temperature Sensor. Check for bad wires.
• If the wires are OK, disconnect the EGT Sensor and check the resistance with an ohmmeter. Compare the results with the manufacturer's specifications. If they do not match, the EGT sensor should be replaced.