What happens to sensors when they are dirty?
When you drive your vehicle every day, it is inevitable the sensors on your vehicle will get dirty. Whether it's water, dust, dirt, road tar or even dead animals in the road, your sensors will get dirty sooner or later. This is why sensors all have special coatings on them and extra rubber insulators to help combat dirt and debris.
There are a lot of sensors on your vehicle, not just for the engine, but also for the transmission and the antilock brake systems; now we even have sensors to help us change lanes on the highway and even stop the car for us. Out of all the sensors we have in our vehicles, today there are some that get abused more than the rest, such as the anti-lock brake sensors that are attached at each wheel so they see the road dirt and debris directly. There are also sensors in your exhaust system called oxygen sensors, or O2 sensors. These particular sensors are exposed to the elements with very little to no coverage like most of the engine and transmission sensors, which have a lot of plastic covers over them to help ward off road dirt. However, the only things you can do are keep your car as clean underneath as you can and make sure to avoid getting the vehicle in situations it should not be in.
If a sensor does get dirty, it could prevent the engine from starting or the engine could run rough or even burn too much fuel. If an ABS sensor gets dirty, the ABS Light will come on in the driver's instrument panel warning you the system has been deactivated. If an oxygen sensor gets dirty, the car's Check Engine Light will turn on; the engine may run too rich and you will see your gas mileage decrease.
In my experience, I have witnessed dirty sensors create all kinds of false problems, such as a Check Engine Light coming on despite no real issues with the vehicle. Intermittent issues with starting the vehicle could happen as well due to a dirty crankshaft position sensor.
Unfortunately, there is really no straight answer to the question except that proper vehicle maintenance and driving habits will help to combat any issues that could arise. It is difficult to detect if sensors are dirty or deteriorating without proper computer equipment. Practice good overall maintenance on your vehicle and take it through a drive-through car wash that cleans the undercarriage of the car. These good habits can extend the time before your sensors get dirty and start causing trouble for your vehicle.
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