The EGTS detects exhaust gas temperature, converts it into a voltage, and sends that voltage signal to the engine control unit (ECU) to monitor engine conditions and effectively reduce emissions.
In petrol engines, if the sensor detects excessive temperatures, the ECU will reduce the temperature by lowering the boost pressure. In diesel engines, the sensor is used to monitor the temperature of the diesel particulate fi lter (DPF) to determine the exact temperature for regeneration.
Where are they located inside the vehicle?
EGT sensors can be found at multiple points in the vehicle’s exhaust system. As they’re used to monitor exhaust gas temperatures and protect critical systems from overheating or failure, these sensors are generally located near these critical system components. For example, one or more EGT sensors may be located near the EGR valve, turbocharger and diesel particulate filter to ensure proper system effi ciency. 
A – Before and after the turbocharger (Turbo)
The EGT sensor fi tted around the turbocharger verifi es that the component temperature has dropped to around 150°C to 200°C for proper operation, while also monitoring the temperature of the component for overheating.
B – Before and after the diesel oxidation catalyst (DOC)
The EGT sensor fi tted around the diesel oxidation catalyst (DOC) is to monitor the inlet exhaust temperature, with a minimum temperature of 200°C required for operation. It also monitors the health of the component, such as for DOC clogging or overheating.
C – Before and after the diesel particulate fi lter (DPF)
The EGT sensor fi tted around the diesel particulate fi lter (DPF) verifi es the DPF regeneration process is complete and effective. It also monitors the health of the component, such as for DPF clogging or overheating.
D – Before and after selective catalytic reduction (SCR)
The EGT sensor fi tted around the selective catalytic reduction (SCR) monitors the temperature of the inlet exhaust, which requires a temperature of around 200°C to 400°C to start working, and that the outlet exhaust has been properly treated.
Features and advantages:
– Single-tube sensor structure for reduced volume size
– High responsiveness due to the sensor and moulded thermistor
– Withstands engine vibrations
– Detects temperature from -40 to 850 degrees Celsius
Benefi ts of a correctly functioning EGT sensor:
– Cleaner exhaust gases, with a reduction of nitrogen oxide (NOx) from the exhaust system
– Improved fuel consumption used in the regeneration (self-cleaning) of the DPF fi lter
– Extended lifespan of the catalytic converter through temperature control, which prevents it from overheating
Typical applications:
– Control and monitoring of the diesel particulate fi lter on diesel vehicles
– Monitoring of SCR ca converters for heavy-duty diesel engines
– Protection of temperature-sensitive components (e.g. turbocharger)
– Integration into on-board diagnostic systems: detection of catalytic converter shutdown temperature
– Monitoring of air injection systems used to shorten the cold start period on petrol engine vehicles
– Detection of temperature window to ensure maximum catalyst effi ciency
– Measurement of exhaust gas temperature EGR

Faulty temperature sensors can cause:
– Unnecessary fi lter regeneration, leading to a reduction of the fi lter’s lifespan
– Energy losses, if the sensor doesn’t detect filter saturation level
– Dashboard light for particulate filter and fl ashing preheat light
– Deterioration of turbocharger, DOC, SCR and DPF components
– Increased oil consumption
– Increased CO, NOx and HC emission levels