Technical Description of OBD-II Trouble Code
The circuit of the Exhaust Gas Temperature (EGT) Sensor for Bank 1 Sensor 1 is registering a low voltage.
What does that signify?
This is a generic powertrain code that applies to all makes and models manufactured from 1996 onwards. However, the specific troubleshooting steps may vary depending on the vehicle.
This diagnostic trouble code (DTC) P0545 pertains to the condition of the EGT (exhaust gas temperature) sensor located in the “up” pipe before the catalytic converter. Its main purpose is to protect the converter from damage caused by excessive heat.
Code P0546 is a similar code that indicates a “high” voltage in the circuit. Both codes relate to the condition of the sensor, and the solution is the same for both. This P0545 DTC specifically refers to Bank #1, which is the side of the engine containing cylinder #1. The DTC P0548 is essentially the same, but it applies to bank 2.
An EGT sensor is present in most modern gas or diesel engines. It functions as a heat-sensitive resistor that converts the exhaust temperature into a voltage signal for the computer. It receives a 5-volt signal from the computer through one wire, while the second wire serves as the ground.
The resistance to ground decreases as the exhaust temperature rises, resulting in a higher voltage. Conversely, as the temperature decreases, the resistance increases, leading to a lower voltage. If the engine detects a low voltage, the computer will adjust the engine’s timing or fuel ratio to maintain an acceptable temperature within the converter.
In a diesel engine, the EGT is used to determine the timing of regeneration of the PDF (diesel particulate filter) based on the temperature increase.
If a catless up pipe has been installed and the catalytic converter has been removed, there is usually no provision for the EGT sensor. If there is a provision, it will not function correctly without back pressure, resulting in the code being triggered.
Symptoms
The check engine light will illuminate, and the computer will store the code P0545. No other noticeable symptoms will be present.
Potential Causes
The potential causes for this DTC may include:
Repair Procedures
Another reason for this code to be triggered is if the catalytic converter has been replaced with a catback system. In most states, this is an illegal modification that can result in a significant fine if caught. It is advisable to check local and state laws regarding the removal of this system, as it leads to uncontrolled emissions being released into the atmosphere. While this may temporarily resolve the issue, it is our responsibility to contribute to keeping the atmosphere clean for future generations.
Until this issue is repaired, the code can be reset by purchasing a 2.2 ohm resistor from any electronics store for a minimal cost. Simply remove the EGT sensor and plug the resistor into the engine side electrical connector. Secure it with tape, and the computer will recognize that the EGT is functioning properly.
