05/20/2025
Informative info that we are all constantlty dealing with!
Brush up on your knowledge of EGT Sensors,
Q: What is the main function of EGT sensors on a diesel vehicle?
A: EGT stands for Exhaust Gas Temperature. The EGT sensors are responsible for reading the exhaust temperatures at various stages in the aftertreatment system and sending this information back to the ECM to maintain proper temperatures for regeneration to reduce harmful emissions.
Q: How many EGT sensors are on a truck?
A: In the aftertreatment system, it's common to have 3 to 5 EGT sensors, so the ECM knows when and how to manage regeneration and SCR operation.
Q: Are there different types of EGT sensors?
A: Yes. NTC and PTC.
NTC (negative temperature coefficient) sensor has a high resistance at low temperatures and a low resistance at high temperatures. Resistance decreases as the heat increases.
PTC (positive temperature coefficient) sensor the resistance increases as the temperature increases. This is the most common type of EGT.
Q: What happens when an EGT sensor fails?
A: If the ECU detects a problem with an EGT sensor a check engine light will come on. A faulty EGT sensor can result in other symptoms including:
Reduced fuel efficiency
Unnecessary DPF regeneration
Failed emissions tests.
Premature exhaust or internal engine component failure
Q: How do I test an EGT sensor?
A: Typically you read it with a scan tool; which is an OEM or aftermarket device that allows you to communicate with the vehicle's ECM. Ohm testing can also be helpful.
Q: What are some common EGT sensor fault codes?
P0544: Exhaust gas temperature sensor, bank 1, sensor 1 - circuit malfunction
P0546: Exhaust gas temperature sensor, bank 1, sensor 1 - high input
P2033: Exhaust gas temperature bank 1, sensor 2 - circuit high
P247A: Exhaust gas temperature sensor bank 1, sensor 3 ā out of range
P0549: Exhaust gas temperature sensor, bank 2, sensor 1 - circuit high
P2031: Exhaust gas temperature bank 1, sensor 2 - circuit malfunction