P0545 indicates the engine control module has detected a voltage signal from the exhaust gas temperature (EGT) sensor on Bank 1 Sensor 1 that is below the expected minimum threshold. This sensor monitors exhaust temperature before the turbocharger or catalytic converter to protect emissions components. A low circuit signal typically means an open circuit, short to ground, or sensor internal failure.
The sensor element has degraded or failed internally, producing a resistance value that reads as a low voltage signal to the control module.
Chafed, melted, or corroded wires in the sensor circuit create an open or short-to-ground condition that pulls the signal voltage low.
Oxidation, moisture intrusion, or a spread terminal at the sensor or module connector increases resistance and distorts the signal.
A leak upstream of the sensor allows ambient air to cool the probe, causing a lower-than-expected temperature reading that may be interpreted as a circuit fault.
Internal driver or pull-up resistor failure in the control module is possible but rare; verify all external wiring and sensor integrity before suspecting the module.
Short trips are possible but extended driving risks catalyst or turbocharger damage from uncontrolled exhaust temperatures; repair promptly.
Not always; wiring faults, connector issues, or exhaust leaks can produce the same code. Diagnose the circuit before replacing parts.
No. Control module failure is very rare for this code. The sensor, wiring, or connectors are responsible in the vast majority of cases.
Yes. A leak upstream of the sensor cools the probe, which can produce a signal the module interprets as a circuit-low fault.