A bidirectional scan tool, like the Launch X431 CRP919E, can be a powerful tool for 4×4 troubleshooting. This article details how such a tool was used to diagnose and resolve a hard starting issue on a 2013 Toyota Tundra Crewmax with the 5.7L Flex Fuel engine. The problem stemmed from a high alcohol fuel density level, causing the engine to incorrectly assume it was running on E85 ethanol fuel. This led to extended cranking, rough idling, strong fuel smells, and reduced gas mileage.
Pinpointing the Problem with a Bidirectional Scanner
The truck owner, experiencing these symptoms, researched and found Toyota Technical Service Bulletin (TSB) 0166-19 (https://static.nhtsa.gov/odi/tsbs/2019/MC-10170730-9999.pdf), which addressed this specific issue. However, the dealership quoted a costly repair of $1200 with a long wait time for the fuel pump. Further research revealed that some owners who had the TSB repair performed experienced a recurrence of the problem.
A potential solution involved resetting the Alcohol Fuel Density level to zero, a procedure achievable with Toyota’s Techstream software. However, using Techstream required either purchasing a potentially unreliable unlicensed version or a costly short-term license. Seeking a more affordable and immediate solution, the owner opted for a bidirectional scan tool capable of performing the reset.
Solution: Launch X431 CRP919E for Fuel Density Reset
After extensive research, the Launch X431 CRP919E emerged as a viable option. The manufacturer confirmed its capability to reset alcohol fuel density levels. Upon receiving the tool, the owner updated the software to include the necessary Special Functions for Toyota vehicles.
Connecting the Launch X431 CRP919E to the Tundra’s OBD-II port, the owner accessed the vehicle’s diagnostic system. The Alcohol Fuel Density Level reading confirmed the suspicion: it was at 85%. Utilizing the Special Functions within the ECM-ECT (engine) section, the “Fuel Density Learning Value Reset” function was executed, successfully resetting the alcohol level to zero in mere seconds.
Results and Long-Term Fix Potential
The results were immediate and significant. The Tundra started without issue, fuel mileage improved, and the engine ran smoother. Subsequent checks revealed the alcohol percentage level remained at zero. While acknowledging the possibility of the problem returning, the owner now possessed a readily available tool for a quick reset, eliminating the need for expensive dealership repairs. This experience highlights the value of a bidirectional scan tool, particularly for 4×4 owners who often encounter unique diagnostic challenges. The Launch X431 CRP919E proved effective in this specific 4×4 troubleshooting scenario, providing a cost-effective and efficient solution to a frustrating problem. Beyond this particular fix, owning a bidirectional scan tool opens up a world of diagnostic and repair possibilities for various vehicle systems.
