Skip to Content

This site is an affiliate for companies including Amazon Associates and earns a commission on qualifying purchases.

How to Reset Honda Grom ECU

How to Reset Honda Grom ECU

The ECU (Engine Control Unit) is a major electronic component that is essentially the brain of the motorcycle’s engine and controls and manages various aspects of the motorcycle’s engine operation. Using the Paperclip Method, you can easily reset the ECU of your Honda Grom by following these four simple steps:

  1. Remove the seat and locate the ECU.
  2. Prepare the paperclip by straightening it into a horseshoe shape.
  3. Reset the ECU by inserting each end of the paperclip into the ECU and turning the ignition on to begin an ECU reset.
  4. Complete the process by removing the paperclip and putting things back together.

What is the ECU?

The ECU (Engine Control Unit), also known as an ECM (Engine Control Module) or PCM (Powertrain Control Module), is a major electronic component that controls and manages various aspects of the motorcycle’s engine operation. It is essentially the brain of the motorcycle’s engine, responsible for monitoring and regulating essential parameters to ensure optimal performance, efficiency, and emissions control.

How to Reset the Honda Grom’s ECU

The Paperclip Method

Resetting the ECU of a Honda Grom using a paperclip is a common method used by motorcycle enthusiasts and Honda Grom owners. Please note that it is very important to exercise caution and ensure you have the proper knowledge and understanding before attempting any modifications or procedures on your motorcycle’s ECU.

Before beginning your Honda Grom ECU reset, ensure that your Honda Grom’s ignition is turned off and remove the key from the ignition switch.

1. Getting Started: To begin the ECU full reset process on a Honda Grom, use your key to remove the seat to locate the ECU/ECM. Locate the diagnostic connector, which is a small 2-pin connector that is usually found near the battery. It may have a rubber cap covering it.

The location of the ECU in the under seat of the 2018 Honda Grom

2. Prepare the paperclip: Straighten out a paperclip into a horseshoe shape and insert one end into each of the diagnostic connector’s pins. This will create a connection between the two pins.

Before and after on how you should straighten out the paperclip

3. Resetting the ECU: With the paperclip in place, turn on the ignition while keeping the paperclip connected. The ECU will enter the reset mode and undergo an ECU flash, indicated by the check engine light flashing or staying illuminated.

4. Completing the Process: After completing this, disconnect the paperclip from the diagnostic connector. This will complete the ECU reset process. You should then put everything back in place, ensuring that all connections are secure and placing the seat back on. Start the motorcycle as you usually would and allow it to idle.

Why Would You Need to Reset the ECU?

Engine Modifications

When you add an engine modification to a Honda Grom, such as installing an aftermarket full exhaust system or air intake, it can potentially affect the behavior and operation of the ECU.

While resetting the ECU after installing an aftermarket modification on your Honda Grom is not always necessary, it can sometimes be beneficial in certain situations.

Examples of engine modifications that could potentially need an ECU reset include:

  1. Change in Air/Fuel Mixture: Engine modifications can alter the air-to-fuel ratio required for optimal combustion. The ECU may need to adjust fuel delivery accordingly to maintain the proper mixture. In some cases, the ECU may be able to adapt and compensate for minor modifications automatically. However, significant changes in airflow or fuel requirements may require recalibration or reprogramming of the ECU.
  2. Performance Mapping: Some engine modifications may provide increased airflow, improved exhaust flow, or changes in engine timing. To take full advantage of these modifications, the ECU may need to be remapped or reprogrammed. This involves adjusting the ECU’s settings to optimize performance, power delivery, and fuel economy based on specific engine modifications.
  3. Check Engine Light: In some instances, adding an engine mod without making corresponding adjustments to the ECU can trigger a check engine light. The ECU monitors various sensors and expects specific values. If it detects deviations from the expected parameters, it may trigger a warning light to indicate a potential issue. To resolve this, the ECU may need to be recalibrated or reprogrammed to accommodate the modifications.
  4. Dyno Tuning: For more significant engine modifications or a combination of multiple mods, it may be necessary to perform dyno tuning. This involves connecting the motorcycle to a dynamometer, which allows technicians to measure real-time performance and make precise adjustments to the ECU settings. Dyno tuning helps ensure that the engine modifications and ECU calibration are perfectly matched for optimal performance.

It’s important to note that the impact on the ECU will depend on the specific engine modifications and how they interact with the motorcycle’s stock ECU programming. In some cases, aftermarket companies offer performance chips or ECU reflash options specifically designed to accommodate certain engine mods, simplifying the process of adapting the ECU to the modifications.

To ensure the best results and avoid potential issues, it is recommended to consult with experienced professionals or specialists who are familiar with the Honda Grom and have expertise in engine modifications and ECU tuning. They can guide you through the process of properly adjusting the ECU to suit the specific engine modifications and help maximize the performance of your Honda Grom.

Conclusion

In conclusion, the ECU (Engine Control Unit) is a major electronic component that is essentially the brain of the motorcycle’s engine. It controls and manages various aspects of the motorcycle’s engine operation and is responsible for monitoring and regulating essential parameters to ensure optimal performance, efficiency, and emissions control on your motorcycle.

Using the Paperclip Method, you can easily reset the ECU of your Honda Grom with the following four simple steps:

Removing the seat and locating the ECU, preparing the paperclip by straightening it into a horseshoe shape, resetting the ECU by inserting each end of the paperclip into the ECU and turning the ignition on to begin an ECU reset, and completing the process by removing the paperclip and putting things back together.

eManualOnline provides descriptive, affordable, and convenient service and repair manuals for cars, trucks, motorcycles, and more. Download one today.