A common problem in modern vehicles is the illumination of multiple warning lights on the dashboard, often without storing a Diagnostic Trouble Code (DTC). This can make diagnosing the issue challenging. This article explores a real-world example of how a car scanner, specifically focusing on the ABS sensor data, helped pinpoint a faulty ABS sensor in a Toyota Land Cruiser Prado 150 (2010).
A Toyota Land Cruiser Prado 150 was experiencing intermittent illumination of warning lights for the ABS, ESP, power steering, and all-wheel drive systems. No DTCs were stored in the vehicle’s memory when the lights were off. The ABS and ESP systems were also reported to be non-functional when the warning lights were illuminated. Given the interconnected nature of modern vehicle systems and the reliance of many systems on ABS sensor data, the ABS sensors were identified as a potential source of the problem.
To diagnose the issue, a car scanner was used with the “Toyota 2010+ OBDII with extra sensors” connection profile selected. This profile allows for individual wheel speed readings. A custom dashboard within the car scanner application was configured to display the real-time speed of each wheel (Front Left, Front Right, Rear Left, and Rear Right). Data recording was also enabled within the car scanner.
After a test drive with the car scanner recording data, the recorded information was analyzed. The four wheel speed parameters were plotted on a single graph for comparison.
The graph clearly showed three wheels reporting consistent speeds, while the front left wheel speed exhibited erratic behavior. Its speed fluctuated significantly, sometimes reading 20-40 km/h less than the other wheels.
This erratic behavior pointed to a problem with the front left ABS sensor or its wiring. The intermittent nature of the fault and the partially correct data from the sensor likely prevented the system from consistently detecting and storing a DTC.
Replacing the front left ABS sensor resolved the issue, confirming the diagnosis made using the car scanner and its ability to monitor individual ABS sensor data. This case study highlights the crucial role a car scanner with ABS sensor monitoring capabilities can play in diagnosing complex automotive problems, especially when DTCs are not available.
