Technical Description of OBD-II Trouble Code
Malfunction in the Circuit of Exhaust Gas Temperature (EGT) Sensor for Bank 2 Sensor 1
What does that signify?
This is a generic code related to the powertrain, applicable to all makes and models from 1996 onwards. However, the specific troubleshooting steps may vary depending on the vehicle.
The diagnostic trouble code (DTC) P0547 indicates a problem with 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 P0547 indicates a general malfunction in the EGR temperature sensor circuit on bank 2, sensor #1. This DTC refers to bank #2, which is the side of the engine without cylinder #1. Related codes include P0548 (circuit low) and P0549 (circuit high).
An EGT sensor is present in most modern gas or diesel engines. It functions as a heat-sensitive resistor that converts exhaust temperature into a voltage signal for the computer. One wire receives a 5-volt signal from the computer, while the second wire serves as the ground.
As the exhaust temperature increases, the resistance to ground decreases, resulting in a higher voltage. Conversely, lower temperatures lead to increased resistance and lower voltage. If the engine detects a low voltage, the computer adjusts the engine’s timing or fuel ratio to maintain an acceptable temperature within the converter.
In diesel engines, the EGT is used to determine the timing of regeneration for the PDF (diesel particulate filter) based on temperature rise.
If a catless up pipe is installed and the catalytic converter is removed, there is usually no provision for the EGT. If there is a provision, it will not function correctly without back pressure, leading to the activation of this code.
Symptoms
The check engine light will illuminate, and the computer will store the code P0547. No other noticeable symptoms will be present.
Potential Causes
Possible causes for this DTC 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 into the atmosphere. While this workaround may function, 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 electronic 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 correctly.
