Experiencing hard starts, poor fuel economy, or a strong fuel odor from your Toyota Tundra, especially if it’s a Flex Fuel model? You might be facing an issue with an incorrect alcohol percentage reading in your fuel system. Many Toyota Tundra owners have encountered a problem where the engine control module (ECM) mistakenly reads a high alcohol percentage, even when using regular gasoline. This can lead to significant performance issues. Fortunately, a solution exists that allows you to address this problem yourself using an Android-based OBD2 scanner.
The Problem: Erroneous High Alcohol Percentage Readings
Some Toyota Tundra Flex Fuel vehicles, like the 2013 5.7L model mentioned in a user experience, can develop a problem where the system incorrectly registers a high alcohol percentage in the fuel, sometimes as high as 85%. This is despite the vehicle running on regular gasoline and not E85 ethanol fuel. This false reading causes the engine to operate as if it’s running on E85, leading to a rich fuel mixture. Symptoms of this issue include:
- Difficulty starting the engine, often requiring extended cranking.
- Rough idling or stumbling after starting.
- Reduced fuel economy.
- A strong smell of fuel, indicating a rich fuel mixture.
Toyota has acknowledged this issue and issued a Technical Service Bulletin (TSB), T-SB-0166-19, to address it. The recommended fix involves dealer service, potentially including fuel pump replacement and software updates.
Dealer Repair: Costly and Inconvenient
While the official fix is available through Toyota dealerships, owners have reported several drawbacks:
- High cost: Dealership repairs can be expensive, with quotes reaching upwards of $1200.
- Parts backorder: Fuel pump replacements, often part of the dealer fix, can be on long backorder, leaving you without a reliably functioning vehicle for an extended period.
- Recurring issue: Some owners have reported that even after dealer repairs according to the TSB, the problem of incorrect alcohol percentage readings can return over time.
The DIY Solution: Android OBD2 Scanner Reset
For Toyota Tundra owners seeking a quicker, more affordable, and potentially longer-term solution, resetting the Alcohol Fuel Density level using an OBD2 scanner presents a viable alternative. This method involves using a bidirectional scan tool to directly reset the alcohol percentage reading in the ECM back to zero.
One tool that has been confirmed to successfully perform this reset on Toyota Tundras is the Launch X431 CRP919E Android OBD2 scanner. This scanner offers bidirectional capabilities and special functions, including the “Fuel Density Learning Value Reset” specifically for Toyota vehicles.
Steps to Reset Fuel Alcohol Percentage Using Launch X431 CRP919E:
- Obtain a Launch X431 CRP919E Scanner: Purchase the Launch X431 CRP919E or a similar Android-based bidirectional OBD2 scanner that explicitly states it supports Fuel Density Reset for Toyota vehicles.
- Update the Scanner: Once you receive the scanner, connect it to Wi-Fi and perform all available software updates. These updates are crucial to access the latest vehicle coverage and special functions, including the Toyota Fuel Density Reset.
- Connect to Your Vehicle: Plug the OBD2 scanner into the OBD2 port of your Toyota Tundra (typically located under the dashboard on the driver’s side).
- Navigate to Special Functions: Turn on your vehicle’s ignition (no need to start the engine). On the scanner, navigate through the menus, typically following these steps:
- Diagnose
- Toyota System Selection
- ECM-ECT (Engine Control Module)
- Special Functions
- Perform Fuel Density Learning Value Reset: Locate and select the “Fuel Density Learning Value Reset” function (or similarly named option). Initiate the reset process. The scanner will communicate with the ECM and reset the alcohol percentage level to zero. This process usually takes only a few seconds.
- Verify the Reset: After the reset, you can check the Alcohol Fuel Density Level reading again using the scanner to confirm that it has been successfully reset to zero.
- Start Your Vehicle: Start your Toyota Tundra. You should notice improved starting, smoother running, and potentially better fuel economy.
Benefits of Using an Android OBD2 Scanner for Fuel Reset:
- Cost-Effective: Purchasing an OBD2 scanner like the Launch X431 CRP919E is significantly cheaper than dealer repair costs.
- DIY Convenience: You can perform the reset yourself in a few minutes, without needing to schedule a dealer appointment or wait for parts.
- Quick Solution: The reset process is fast and provides immediate relief from the symptoms of incorrect alcohol readings.
- Multi-Functional Tool: OBD2 scanners are versatile tools that can be used for various diagnostic and maintenance tasks on multiple vehicles, not just fuel resets. They can read and clear trouble codes, perform other resets, and access live data, making them a valuable addition to any car owner’s toolkit.
Conclusion:
If you are experiencing fuel-related issues with your Toyota Tundra Flex Fuel vehicle and suspect an incorrect alcohol percentage reading, an Android OBD2 scanner like the Launch X431 CRP919E offers a practical and efficient DIY solution. Resetting the fuel density learning value can resolve hard starting, improve fuel economy, and restore smooth engine operation. While dealer repairs remain an option, the OBD2 scanner method provides a compelling alternative for those seeking control, convenience, and cost savings in maintaining their vehicles.
