To access the battery backup for your main ECU, remove the 7.5A number 2 fuse from the fuse box and remove it for 2 seconds before replacing. Your engine control unit’s learning values and fuel trims have now been reset.
In This Article...
How can an ECU be reset without the battery being removed?
Easy Method to Reset ECU without Disconnecting the Battery
- Push the Engine Start button TWICE while holding the key in your pocket or car (so the car is fully on, but not started)
- When the car is “ON” for three seconds (again, NOT started), press and release the gas pedal fully five times in quick succession.
Resetting the ECU after unplugging the battery?
A. The age and kind of the car’s ECU are key factors. Disconnecting the battery may reset the system in some older vehicles, but in the majority of modern vehicles, it usually has no effect other than possibly resetting the clock and radio station presets.
In a contemporary car, if you accelerate quickly, the ECU will automatically regulate the air temperature, engine temperature, and fuel usage to the best of its ability based on the driving conditions.
For auto gearboxes, certain ECUs offer “adaptive learn” capabilities. They can modify the points at which they shift gears and sharpen throttle reactions if they notice a pattern of aggressive driving.
What occurs when I reset the ECU?
The procedure of “resetting the ECU” involves erasing all of the long term memories from the device’s memory. These controls alter the fuel, spark, idle speed, and other factors. Additionally, the ECU will keep error codes for diagnostic purposes.
How can you tell if your ECU needs repair?
Here are the most typical signs of an unhealthy ECU:
- After being reset, the Check Engine Light remains on.
- Reverse polarity jump-started the car.
- Unexpected engine shutdown.
- The ECU has suffered water or fire damage.
- apparent spark loss
- apparent loss of the fuel pump or the injection pulse.
- irregular starting issues.
When resetting a computer, how long do you disconnect the battery?
Yes, one way to reset the check engine light is to disconnect the engine. The majority of sources advise leaving the battery disconnected for at least 15 minutes to ensure the computer forgets the code before you reconnect the battery because some of the electrical current is kept in the computer for some time afterward.
Other experts advise draining any remaining electricity on the computer after removing the engine by turning on the light switch for a few minutes (the lights won’t turn on).
Before you take this approach, keep in mind that there are certain drawbacks to this way of turning off your check engine light. If your car was made after 1996 and you have access to one of these tools, such as this one available on Amazon, you can also use it to reset the fault codes if you’d prefer not to deal with those.
It’s never too late to start learning how to properly take care of and maintain your car. We value the time you invested in learning how to properly disconnect your battery. For whatever reason you need to disconnect it, be sure to hire a pro to ensure your safety and the safety of your belongings.