Technical Description of OBD-II Trouble Code
Circuit for Exhaust Gas Temperature EGT Sensor, Bank 1 Sensor 2
What is the meaning of this code?
This code is a generic powertrain code that applies to all makes and models from 1996 onwards. However, the specific troubleshooting steps may vary depending on the vehicle.
DTC P2031 refers to 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 P2031 indicates a general malfunction in the EGR temperature sensor circuit on bank 1, sensor #1. This DTC is related to Bank #1, which is the side of the engine containing cylinder #1. Other related codes are P2032 (circuit low) and P2033 (circuit high).
An EGT sensor is present in most modern gas or diesel engines. It is essentially a heat-sensitive resistor that converts 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.
Here is an example of an EGT exhaust temperature sensor:
The resistance to ground decreases and the voltage increases as the exhaust temperature rises. Conversely, the resistance increases and the voltage decreases as the temperature decreases. 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 rise.
If a catless up pipe is installed and the catalytic converter is removed, there is usually no provision for the EGT sensor, or if there is, it will not function correctly without back pressure. This will trigger the code.
Symptoms
The check engine light will illuminate and the computer will store the code P2031. No other noticeable symptoms will be present.
Potential Causes
The possible causes for this DTC may include:
P2031 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 temporarily reset the code, it is our responsibility to contribute to keeping the atmosphere clean for future generations.
If it is not possible to mechanically resolve this issue, we offer the option to permanently delete this specific DTC. All other codes will continue to function. If you are interested in this option, please upload your ECU file to our portal.
