P0544 indicates a problem in the electrical circuit for the exhaust gas temperature (EGT) sensor located on Bank 1, Sensor 1. The powertrain control module has detected a voltage, resistance, or signal value outside the expected range, meaning it can no longer reliably read exhaust temperature at that location.
The sensing element or internal wiring of the EGT sensor can degrade from repeated thermal cycling and contamination, producing an out-of-range signal.
Heat, vibration, chafing, or corrosion in the harness and connector near the exhaust can cause opens, shorts, or high resistance in the sensor circuit.
A short to ground, short to voltage, or broken wire between the sensor and the control module disrupts the voltage signal the module expects.
Leaking hot exhaust gases or heavy soot buildup can alter temperature readings or damage the sensor tip, leading to erratic circuit readings.
Only after the sensor, wiring, and connectors are verified good should a PCM signal-conditioning problem be considered, as this is uncommon.
Short trips are usually possible, but prolonged driving can lead to DPF regeneration failure, turbocharger stress, or limp mode. It is best to diagnose it promptly.
Usually not. The problem is far more often the EGT sensor itself or its wiring. The PCM should be suspected only after the sensor and entire circuit have been tested and confirmed good.
It is the first exhaust gas temperature sensor on the bank of cylinders containing cylinder 1, typically mounted in the exhaust manifold, up-pipe, or just ahead of the turbocharger or DPF.
P0544 is a general circuit/range fault. P0545 usually indicates a low input signal and P0546 a high input signal, though exact definitions can vary by manufacturer.