Check Engine Light
When you see the check engine light on your dash come on, your heart drops. You start paying attention to how your car is running and wonder if it’s going to cost you an arm and a leg to fix.
Why the Check Engine Light Comes On
Your vehicle’s control module sends and receives information to and from various sensors on the vehicle. These sensors keep the engine running within certain parameters for emissions. If something is out of whack and the control module cannot adjust for it, the control module stores a code and turns the check engine light on.
An ASE-Certified technician uses a diagnostic tool that interfaces with the control module to convert the codes from a number to a problem. However, it is not as simple as reading the code and replacing the sensor indicated on the diagnostic tool.
Limitations of Diagnostics
The diagnostic tool only tells the mechanic which sensor is out of range. It is up to the auto technician to determine why the sensor is out of range and to make the appropriate repairs.
For example, if the code translates to a knock sensor, that doesn’t mean that the knock sensor failed.
The knock sensor senses abnormal combustion – either pre-ignition knock or detonation. It sends a message to the computer that the engine is knocking or pinging.
In some cases, you can hear it, but the knock sensor senses light detonation and pinging before the human ear can hear it.
The auto tech must determine what is causing the detonation or if the sensor truly failed. Once the tech determines whether there is a true knock or the sensor failed, then he can make the appropriate repairs.
Limp Home Mode
In some cases, the check engine light comes on, but you can still drive the vehicle.
If the problem is serious enough, limp home mode reduces the power available. It gives you just enough power to get to where you can safely pull off the road, to an auto repair shop, or home.
If you shut the vehicle off once it goes into the limp home mode, chances are good that it won’t start again.
If you notice that your vehicle doesn’t seem to have the power it should and the check engine light is on, get it to our auto repair shop at Repair One as soon as possible.
If you are out on the road and within a few miles of us, the limp home mode should get you here. If you went home or pulled off and shut the vehicle off, you should have a tow truck bring your vehicle to us even if it starts again. In some cases, running it with a potential serious problem could cause more damage.
Contact Repair One for Diagnosing and Resolving Check Engine Light Issues
When you need a check engine light diagnosed, contact Repair One for an appointment or call us when the tow truck is on the way with your vehicle.