How to Reset the Check Engine Light
You’re driving home from work, wondering what movie to watch after the kids go to bed, when suddenly the bright orange money light lights up on your dashboard.
Your heart races as you prepare for the self-destruct sequence. But wait… is your car still in working order? Maybe you can get home after all!
If you’re reading this article, your check engine light is probably on and you’re not sure what to do next. Don’t worry, the check engine light is very common. Most car owners have experienced them at some point, especially if they own an older vehicle.
What is a Check Engine Light?
Your vehicle’s Engine Control Unit (ECU) is designed to measure and check values ​​from each of your vehicle’s sensors. If any of these values ​​fall outside of expected ranges for a specific amount of time or a specific number of occurrences, the Check Engine Light will come on.
OBD is a common interface for reporting errors or malfunctions in vehicle sensors, especially the exhaust system, detected by the ECU.
Vehicles manufactured after 1996 have an improved version of on-board diagnostics called OBD2. OBD2 systems are consistent across different makes and models, have more information available, and are easier to scan.
When the check engine light comes on, many car enthusiasts refer to it as a “code problem.” What does the check engine light mean? If the check engine light is on, your vehicle has detected a problem with one of its systems, so the stored codes can be very helpful when you or a mechanic begin to diagnose the problem.
Why is my check engine light on?
The check engine light can come on for a variety of reasons, or a combination of multiple faults. A. The sensor may be faulty. B. The Mass Air Flow Sensor (MAF) or Oxygen Sensor (O2). The ECU may have detected a misfire or your vehicle may be running too rich or too lean.
Is it safe to drive with the check engine light on?
You might be surprised, but in many cases it is safe to drive with the check engine light on. This depends heavily on the actual problem, but if your car is otherwise running fine, it is probably safe to carefully drive your car to a mechanic and have the shop inspect the car. Your vehicle may run at significantly reduced fuel consumption until the problem is fixed. If your car feels rough or erratic, stop as soon as it is safe to do so and have your car towed to the nearest repair shop to have the problem diagnosed.
What happens if I leave the check engine light on?
Even if your car is running fine, we recommend not leaving the check engine light on for any longer than necessary. In more severe cases, if one or more sensors show very abnormal values, your car may go into limp mode (a fail-safe mode that severely limits the vehicle’s performance). Your engine could have several faulty components. If your Check Engine Light is already on, you won’t notice if another component is throwing a different code because the Check Engine Light is already on on your dashboard.
If you live in an area with emissions testing, your vehicle may fail inspection if the Check Engine Light is on.
How do I reset the Check Engine Light? Note: Resetting the Check Engine Light will not repair your vehicle. This code will probably appear again soon. OBD1
For pre-1996 vehicles with an OBD1 system, you may be able to read the codes using jumper cables or paper clips. Connect the cable between the ground (GND) pin and the Check Engine Light (TEN) pin located in the diagnostic box under the hood. Different vehicles have different names for the TEN pin.
The OBD1 interface is not very standardized, so you will likely need to consult your repair manual for instructions on how to specifically read and clear codes for your vehicle. If you don’t have access to a repair manual, try doing a Google search using a query like “1994 Mazda Protege check engine light reset,” substituting the year, make, and model.
OBD2
If you want to reset the check engine light, you will need an automotive diagnostic tool. These tools can often be rented from an auto parts store or found inexpensively online. Most diagnostic tools allow you to clear diagnostic trouble codes.
Disconnect the battery ground
Regardless of the OBD interface, you can usually reset the check engine light by disconnecting the battery ground. Note that this may also reset other vehicle settings such as: B. Your favorite radio stations. Vehicle Readiness Checks
Vehicles perform certain “readiness checks” to ensure all systems are functioning properly. These readiness checks often require you to drive in a certain way for a certain amount of time while the ECU runs through its internal checklist.
This means that you may not pass an emissions inspection, even if the check engine light is off. Depending on your vehicle and specific driving conditions, it may take up to a week to complete all readiness checks.
Conclusion
Though it may seem scary at first, the check engine light is usually nothing to be afraid of. There are diagnostic trouble codes that can help you and the technician diagnose minor issues with your vehicle before they develop into major problems.
Many auto parts stores offer this service for free. If you want to own your own diagnostic tool, check out our list of the best diagnostic tools currently available on the market.
