Encountering hard starts and reduced fuel efficiency in your Toyota Tundra? You might be facing a common issue related to the Flex Fuel system misreading the alcohol percentage in your fuel. Many Toyota Tundra owners, particularly those with Flex Fuel models, have experienced a frustrating problem where the engine control module (ECM) incorrectly registers a high ethanol content, even when running on regular gasoline. This misreading can lead to a cascade of issues, including prolonged engine cranking, rough starts, a rich fuel mixture causing stumbling, noticeable fuel odors, and a significant drop in gas mileage.
One Tundra owner with a 2013 5.7L Flex Fuel Crewmax faced this exact scenario. Despite never using E85 fuel, their vehicle began exhibiting classic symptoms of running on high ethanol content. Seeking a solution, they discovered Toyota’s Technical Service Bulletin (TSB) T-SB-0166-19, which addresses this very problem. The TSB outlines a dealer-level fix, often involving fuel pump replacement and a software update. However, dealer quotes for this service can be steep, often around $1200, and parts may be back-ordered, leaving owners in a bind. Moreover, some owners who opted for the dealer fix reported the issue recurring later on.
For those seeking a quicker and potentially more cost-effective solution, resetting the Alcohol Fuel Density level to zero can provide immediate relief. While some adventurous owners have attempted to use Techstream cables and software – often aftermarket versions – to reset this parameter, the process can be technically challenging and fraught with software compatibility issues. The online forums are filled with accounts of users struggling to get these systems to work correctly. Avoiding the complexities of Techstream and the expense of a Toyota dealer service, the Tundra owner in question explored alternative diagnostic tools.
Their search led them to the Launch X431 CRP919E automotive scan tool. This bidirectional scan tool emerged as a promising option for resetting the alcohol fuel density level without breaking the bank. While other tools like the XTOOL D7 and D8 were considered, direct confirmation from XTOOL indicated they did not support this specific reset function for Toyota Tundra at the time. Prior to purchasing the Launch X431 CRP919E, the owner verified with the seller on Amazon that the tool indeed supported the required function for a Toyota Tundra.
Upon receiving the Launch X431 CRP919E, the user, new to scan tools, easily updated the device software to access the necessary Special Functions for Toyota vehicles. Connecting the tool to their Tundra, they first confirmed the excessively high Alcohol Fuel Density Level reading of 85%. Then, navigating through the intuitive menu, they accessed the ECM-ECT (Engine Control Module) diagnostics, located the Special Functions menu, and selected “Fuel Density Learning Value Reset.” This function, executed within seconds, effectively reset the alcohol percentage level to zero.
The results were immediate and transformative. The Toyota Tundra started promptly without hesitation, fuel economy improved noticeably, and the engine ran smoother overall. Subsequent checks confirmed the alcohol percentage level remained at zero after the reset. The owner now has a readily available solution should the issue recur. The convenience of quickly resetting the alcohol level with the Launch X431 CRP919E, in about two minutes, provides significant peace of mind.
Beyond this specific Flex Fuel issue, the Launch X431 CRP919E offers a wide range of diagnostic and service functions for various vehicle makes, including European brands like BMW, as highlighted by the user’s mention of using it for their wife’s BMW. This versatility makes the Launch X431 CRP919E a valuable tool for any DIY mechanic or car owner looking to take control of their vehicle maintenance and diagnostics. For Toyota Tundra owners experiencing Flex Fuel related problems, the Automotive Scan Tool Launch provided by the Launch X431 CRP919E offers a user-friendly and effective solution, saving both time and money compared to dealer visits or complex software workarounds.
