The advent of the autonomous car has highlighted the fundamental importance of having good sensors. That being said, we have long been committed to providing effective – and reliable – sensors to our customers. So whether you are looking for engine and transmission sensors, or for comfort and safety – not to mention emissions and e-mobility – you should definitely take a look at our range.
Located along the exhaust line (as its name implies), the temperature sensor measures the exhaust gases’ temperature in order to limit pollutant emission. This information is transmitted directly (via a voltage signal) to the electronic control module (ECM) in order to optimize combustion – to make it as clean as possible, either by adapting the air/fuel mixture, or by initiating a regeneration of the diesel particulate filter (DPF).
Originally protecting only the catalytic converter, in the exhaust system, the exhaust gas temperature sensor’s role is pivotal. As a matter of fact, it also protects the components in the exhaust gas stream, which are exposed to extremely high temperatures. The sensor is capable of measuring temperatures ranging from -40 to +900°C and its presence in a particularly harsh environment exposes it to a high risk of failure (compared to other sensors).
Due to increasingly strict anti-pollution standards, modern vehicles (petrol and diesel engines) are equipped with several sensors. Generally, they have at least 3 sensors, one before the turbocharger, one before the DPF and one after the DPF.
NTC TYPE THERMISTOR
NTC (Negative Temperature Coefficient) thermistors work as follows: as the exhaust gas temperature increases, the resistance value will gradually decrease.
PTC TYPE THERMISTOR
PTC (Positive Temperature Coefficient) thermistors work in the opposite way; thus when the exhaust gas temperature increases, the resistance value will increase in the same way.
Note: this thermistor is the most common on the market, but in both cases a temperature is assigned to the ECU resistor.
SYMPTOMS
The following symptoms are frequently associated with an exhaust gas temperature sensor failure:
DIAGNOSIS PROCEDURE
First and foremost, you need to visually inspect the exhaust gas temperature sensor to determine the presence of a fault. It is therefore strongly recommended to check the following:
Using a multimeter, you can also check whether the exhaust gas temperature sensor is functional. First, the multimeter should be connected to the sensor connector and the side where the sensor is located should be heated. By setting the multimeter to 20M Ω, and depending on the sensor type (NTC or PTC type – see “Technologies” section), either the resistance will increase when the temperature increases (PTC type), or conversely it will decrease when the temperature increases.
If the above tests are not conclusive, you will probably need to replace your exhaust gas temperature sensor.
CAUSES OF FAILURE
It is possible that an exhaust gas temperature sensor is no longer working due to:
INSTALLATION INSTRUCTIONS
To ensure a quick and efficient installation, you must refer to the following instructions:
If necessary, connect the diagnostic tool to clear any fault codes.
INSTALLATION TIPS
As the exhaust gas temperature sensor is essential to the correct operation of the engine, it is important to follow a certain number of recommendations when replacing it:
PREVENTIVE INFORMATIONS
The above items are provided for information purposes only. They do not replace the advice of a qualified technician or mechanic. We strongly recommend that you consult a professional if you are unsure of what to do. Otherwise, we cannot accept responsibility for any damage to your vehicle.
When an exhaust gas temperature sensor fails, the engine light (an amber light) comes on, or the glow plug light flashes. Your vehicle’s fuel consumption will increase, and so will its pollutant emissions. Without the correct information, your particulate filter may start untimely regeneration cycles, which may lead to premature failure of other components in the exhaust system and/or engine.
First of all, you should visually check the exhaust gas temperature sensor; i.e., the sensor itself (presence of dirt), the connector (presence of corrosion and/or looseness) and its wiring (not damaged or broken).
Secondly, you can test your sensor’s correct functioning by checking its resistance. By plugging the measuring tool into the sensor connector and heating the side where the probe is located, you can check whether the resistance fluctuates. However, you will need to make sure that you have set the multimeter to 20M Ω, and that you know which technology your sensor uses (NTC or PTC type – see “Technologies” section). Depending on the sensor type, either the resistance will increase when the temperature increases (PTC), or conversely it will decrease when the temperature increases (NTC).
If the above tests are not conclusive, then it would appear that you need to replace your vehicle’s exhaust gas temperature sensor.
Although automotive sensors meet very strict standards, they do not last forever. Several elements may also fail, thus requiring replacement; among which a broken sensor cable (which may be due to torsion and/or internal vibration on the exhaust line), or a torn wire connecting the sensor to the ECU. The sensor may also have been damaged by a liquid, such as antifreeze or oil. Of course, time-related wear and tear is also a potential cause of failure, but that goes for any type of product.
We recommend the following steps to replace your exhaust gas temperature sensor as efficiently as possible and to limit possible mistakes:
As a sensor specialist, we recommend the following to extend your exhaust gas temperature sensor’s durability:
