The electronic control unit or ECU was originally developed in the 1970’s. Since then there have been continual changes and technological improvements in car manufacturing. Most modern cars now have an ECU which is in contact with the sensors throughout the automobile. Most cars also share the same type of sensors just made by different manufacturers for their cars.
When you own a Lexus, it is important to have the car manual at hand and be aware of what sensors are in your car and how each sensor works. You need to notice if the sensor lights are lit which means you need to drive in to let our certified automotive repair experts take a look.
To obtain your Lexus manual go to drivers.Lexus.com, entering your vehicle model and year at the bar at the top where it reads “Select A Vehicle.” Then you can download the PDF form of your auto repair manual or you may also request a hard copy to be mailed.
Two of the sensors you will want to understand are the air fuel ratio sensor and the oxygen sensor. It would be easy to think these sensors do the same thing but there are some differences.
Cars have had oxygen sensors since the 1980’s, but in the early 2000’s, more accurate sensors were developed leading to the air fuel ratio sensors (A/F). The A/F sensor takes note of the oxygen content of the car’s exhaust in a more expansive, effective way. Even though it looks similar to the oxygen sensor, it has more visible wires. The A/F can sense a much larger and leaner span of fuel mixtures. Due to this ability, it is also called a wideband or broadband sensor.
The air fuel ratio sensor is typically in the exhaust manifold or in the front exhaust pipe. It measures the oxygen in the exhaust and sends that information to the ECU. The ECU, based on the air-to-fuel ratio, adjusts the blend to keep it at the prime level. This level is generally 14.7:1. It is important that the A/F sensor remain in good condition in order to keep your car running at this optimum level.
The oxygen sensor (O2) is an important part of your car’s emissions system and has been since the initial use of ECUs. The O2 sensors were created to keep tabs on how much oxygen is in your vehicle’s exhaust stream checking for efficiency confirming that the catalytic converter is functioning properly.
The sensor notes whether the air/fuel mixture is too lean or too rich. That knowledge is sent back to the ECU which adjusts the metering and timing of the fuel to make sure your car is running on the proper mixture. These readings change as you go up hills, accelerate, have just begun driving, change engine temperature and other elements. Since your car has two sensors checking the exhaust, the O2 sensor will be on the other side of the catalytic converter from the A/F.
Newer vehicles, like your Lexus or luxury car, have both sensors. One is “downstream” of the converter and the other is “upstream.” The reasoning behind having both sensors is to better calibrate the information the ECU receives. In short, two readings are better than one. These readings will give the information necessary to make sure your car is working at the top performance level which will affect a number of things including quality of the ride and your gas mileage. Cars and trucks with dual exhaust have two sensors on each exhaust pipe.
If you have any questions regarding the air fuel ratio sensor or the oxygen sensor in your Lexus, please contact Earnhardt Lexus or our service department to learn more. Remember that it is important to pay attention to the sensor warning lights to make sure your car is evaluated thus keeping it running smoothly and at the level you expect from a luxury brand.