In order to meet Federal Exhaust
Emission and Fuel Economy regulations, today's vehicles are
equipped with highly sophisticated electronic engine control
systems. These systems do not require periodic adjustments. The
only services required on a scheduled basis are spark plug and
filter replacement. Tune-ups, as we knew them, are no longer
Engine Control Computer
The computer receives information from a network of sensors and
switches that convert engine operating conditions into electrical
signals. Based on the information and instructions stored in the
computer program, commands are then sent to three primary systems:
Emission Control System
The sensors that monitor one or more of these systems include:
1. Mass Airflow Sensor
2. Throttle Position Sensor
3. Manifold Absolute Pressure Sensor
4. Coolant Temperature Sensor
5. Exhaust Oxygen Sensor
6. Crankshaft Position Sensor
7. Camshaft Position Sensor
When your check engine light comes on, you may be
torn between utter panic and just wanting to ignore it and hope it goes away. That’s perfectly understandable. That same
check engine light could come on for anything from a serious engine or transmission problem all the way down to a loose gas
There’s a very common misconception that the trouble codes stored in your engine computer when your check engine light comes
on will specifically identify a problem. It’s really more like pointing to the symptoms of a problem.
Call Yeck’s Tire & Auto Repair at 402.293.1200 for help with your check engine light.
Think of taking your temperature. Say it’s 101. Your heat sensor – the thermometer – tells you that your temperature is out
of the normal range. But it doesn’t tell you why you have a fever. Is it the flu or a sinus infection? You need more
information; more tests.
For any given trouble code, there could be a number of causes. So your trained technician takes the trouble code as a
starting point and begins a diagnostic process to determine the cause of the problem. And some problems take longer to solve
When your engine management system logs a problem and illuminates the check engine light, your Bellevue service technician
at Yeck’s Tire & Auto Repair will plug in a scanner, download the trouble codes and go to work tracing the cause of the
That’s just the first step. That’s when your technician’s training, equipment, databases and skill get put to work
diagnosing the problem and fixing it.
If your check engine light is flashing it means that the problem could lead to serious damage. You should get to your local
Bellevue NE service center as soon as possible to get the problem solved. If it’s on but not flashing, you have some time to
get in at your convenience.
Air and fuel are mixed together to be burned in your engine. You request how much of each you need by how
hard you press on the accelerator, by going up or down a hill or by how much you are carrying in your vehicle as your drive
around Bellevue. Based on how much air you need – and how much is available – your engine management computer sends the
needed amount of fuel to your engine. But what if the computer is getting the wrong information about how much air is coming
into your engine? Well, it would send get the wrong amount of fuel and your engine wouldn't perform the way you need it to.
The Mass Air Flow (MAF) sensor measures the volume, temperature and density of the air coming into your engine. With that
information, the computer calculates how much oxygen is available to burn and adjusts the amount of fuel it sends. A dirty
or damaged MAF sensor will provide inaccurate air flow readings, which can lead to drivability problems, damage your
catalytic converter, set off the Check Engine light and may even prevent the engine from running.
The good news is that Bellevue drivers can prevent most MAF sensor contamination. As air comes into your engine, it first
passes through the engine air filter. Dust, road grime, pollen and other contaminants are captured in the filter. When the
engine air filter becomes very dirty and clogged, some of the contaminants pass through the filter and hit the MAF sensor.
That is how the sensor can become so dirty or damaged that it cannot accurately measure the air flow. So replacing your
engine air filter as recommended will extend the life of your MAF sensor and help keep your engine running smoothly.
Now if your MAF sensor is contaminated, it may be possible to clean it with an air induction cleaning service at Yeck's Tire
& Auto in Bellevue. This service also cleans your throttle body and other fuel system components. In those circumstances
where the MAF sensor has been damaged, it will need to be replaced.
Approximately 12,000 gallons of air pass through your engine air filter for every gallon of fuel you burn (45,000 liters of
air for every 4 liters of fuel). That's a lot of air to clean – and your air filter must be up to the job. Replacing this
relatively inexpensive part will not only prevent dirt from getting into your engine, it will help keep your MAF sensor
functioning properly. Your technician can easily inspect your engine air filter to see if it should be replaced. A caution:
low-line air filters may actually contribute to MAF sensor failure as filter material can come loose and contaminate the
sensitive sensor elements. A good quality engine air filter is your engine's first line of defense.
When your Yeck's Tire & Auto Service Advisor recommends you replace your engine air filter, you now know how much is riding
on that simple part.
The oil and fuel in your vehicle give off vapors that are very harmful to the environment. Evaporative emissions control
systems – EVAP for short – are mandated in all cars and trucks. The EVAP system is there to capture these vapors and direct
them into the engine to be burned – kind of an on-board recycling program.
The EVAP system is a complicated network of hoses, valves, filters and such. Issues with the EVAP system are in the top 5
reasons for a Check Engine light to be illuminated. Your friendly and knowledgeable Yeck's Tire & Auto service advisor can
pull the trouble codes and begin a diagnostic procedure to isolate the fault.
With the proper equipment, your technician can test the valves in order to trace a blockage. A low pressure smoke test can
be performed to find any leaks. The repairs are then made to get the EVAP system working again and to reset the Check Engine
While EVAP problems don't generally lead to vehicle damage, the fact that they trigger the Check Engine light can mask other
more problems for Bellevue residents if left unaddressed. After all, there are hundreds of conditions that can trigger a
Check Engine light, but there is only one light. So if the light is on because of an EVAP issue you haven't fixed and
another arises, you won't be alerted to the new condition because the light is already on.
Of course, if you live in a jurisdiction in NE that requires emissions testing to register your vehicle, you won't pass the
test until you make the repairs. An EVAP trouble code could be caused by something as simple as a loose or worn gas cap, a
leak in a hose, problems with a purge valve or even a rusty fuel filler pipe.
When your Check Engine light comes on, bring your vehicle into Yeck's Tire & Auto in Bellevue and let us check it out. Your
Yeck's Tire & Auto service advisor will be able to diagnose the system and work out a plan to address any problems that are
uncovered. There's peace of mind for Bellevue drivers that comes from knowing what is wrong and taking care of it.