Diagnosing fuel system issues can be complex, but with the right auto scan tool, even challenging problems like high alcohol fuel density can be addressed. This article outlines how a Launch X431 CRP919E bidirectional scan tool was successfully used to diagnose and resolve a fuel-related starting problem on a 2013 Toyota Tundra. The process highlights the importance of Auto Scan Tool Fuel System Diagnosis for accurate and efficient troubleshooting.
Pinpointing the Problem: High Alcohol Content
A 2013 Toyota Tundra 5.7L Flex Fuel engine experienced hard starting, rough running, strong fuel smells, and reduced fuel economy. After researching, the issue was linked to a high alcohol fuel density level. Despite never using E85 ethanol fuel, the engine control module (ECM) incorrectly registered a high alcohol percentage (85%), causing the fuel system to operate with an overly rich mixture.
Toyota issued Technical Service Bulletin (TSB) 0166-19 to address this problem (https://static.nhtsa.gov/odi/tsbs/2019/MC-10170730-9999.pdf), but the dealership quoted a costly repair ($1200) and a long wait for parts. Alternative solutions involved using a Techstream cable with potentially unlicensed software, which presented its own set of challenges.
Figure 1: The Launch X431 CRP919E scan tool, used for diagnosing and resolving the high alcohol fuel density issue.
Solution: Launch X431 CRP919E for Fuel Density Reset
A more immediate and cost-effective solution was found using the Launch X431 CRP919E bidirectional scan tool. This auto scan tool provides the necessary functionality for fuel system diagnosis and allows for resetting the alcohol fuel density level. Other scanners like the XTOOL D7 and D8 were considered, but they lacked this specific capability for the Tundra.
Figure 2: The Launch X431 CRP919E connected to the vehicle’s OBD-II port, ready to perform diagnostics.
After updating the Launch X431 CRP919E to access the necessary special functions for Toyota vehicles, the scan tool confirmed the high alcohol density reading of 85%. Utilizing the “Fuel Density Learning Value Reset” function within the ECM-ECT (engine) special functions menu, the alcohol level was successfully reset to zero. This process took only a few seconds.
Results and Conclusion: Effective Auto Scan Tool Fuel System Diagnosis
Following the reset, the Tundra’s starting problems, rough running, and poor fuel economy were completely resolved. The engine started immediately and ran smoothly, demonstrating the effectiveness of the auto scan tool fuel system diagnosis and reset procedure. The alcohol percentage level remained at zero after subsequent checks.
Figure 3: The Toyota Tundra’s 5.7L engine, running smoothly after the fuel density reset.
The Launch X431 CRP919E proved to be a valuable tool for auto scan tool fuel system diagnosis, offering a quick and affordable solution to a complex problem. This experience highlights the potential of using advanced diagnostic tools to troubleshoot and resolve vehicle issues without relying solely on expensive dealership repairs. Should the problem reoccur, the readily available scan tool allows for a simple and efficient reset procedure.
