Fuel Density Learning Value Reset (1)

How to Access the Fuel Density Learning Value Reset in the OBD Scanner

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Guide on How to Access the Fuel Density Learning Value Reset in the OBD Scanner

The “Fuel Density Learning Value Reset” function in an OBD (On-Board Diagnostics) scanner is related to the vehicle’s fuel trim and fuel delivery system.

Modern vehicles with electronic fuel injection systems use adaptive learning strategies to compensate for variations in fuel properties, engine wear, and other factors that can affect the air-fuel ratio. The engine control module (ECM) continuously monitors the air-fuel ratio and makes short-term and long-term adjustments to the fuel trim values to maintain the ideal air-fuel mixture.

The fuel density learning value is a long-term adaptive fuel trim value that the ECM learns and stores to compensate for variations in the density of the fuel being used. This value helps the ECM adjust the fuel injector pulse width to deliver the correct amount of fuel based on the fuel’s density.

The “Fuel Density Learning Value Reset” function in the OBD scanner allows you to reset or clear this learned fuel density value stored in the ECM’s memory. This reset may be necessary in certain situations, such as:

1. After replacing the ECM or reprogramming the ECM software.
2. After performing a major service or repair that could affect the fuel delivery system, such as replacing fuel injectors or the fuel pump.
3. If the vehicle has been running on a significantly different fuel density (e.g., switching from regular gasoline to premium gasoline or vice versa).

By resetting the fuel density learning value, you are essentially telling the ECM to relearn and adapt to the current fuel density from scratch. This can help resolve issues related to the air-fuel ratio, fuel trim, or driveability problems that may occur due to an incorrect learned fuel density value.

It’s important to note that after resetting the fuel density learning value, the vehicle may experience a temporary decrease in fuel economy and driveability until the ECM has had sufficient time to relearn and adapt to the new fuel density.

Instruction to Access the Fuel Density Learning Value Reset in the OBD Scanner

The Fuel Density Learning Value Reset can be accessed by following this instruction.

  1. Open your OBD scanner.
  2. Select Local Diagnose if you are using Launch X431.
  3. Select Car Brand Select Model (auto-detect is better to detect the vehicle VIN).
  4. Select and check the following: ECMECT (Engine and ECT), ECM (Engine Control Module)
  5. Select Special Function Then click Fuel Density Learning Value Reset.

The sample car model with this feature is the Toyota Camry 2009 till to the current Year model.