A Ford truck experiencing recurring ABS and traction control warning lights, along with the U0415:00:08 code pointing to the right rear (RR) wheel speed sensor, was diagnosed and repaired. Initial code clearing after sensor replacement proved ineffective, as the code immediately reappeared. However, a subsequent test drive revealed normal readings from all four wheel speed sensors after a short distance. The warning lights extinguished and remained off for approximately seven miles, indicating a successful repair.
The previous failure to clear the code and persistent warning lights, coupled with the successful extended test drive following the sensor replacement, strongly suggests the new sensor resolved the issue. The old sensor exhibited significant metallic sludge buildup, reminiscent of debris found within transmissions or differentials. Although cleaning the old sensor was considered, concerns regarding the damaged gasket and potential resealing issues led to the decision to proceed with replacement.
The visual inspection of the old sensor supports the diagnosis, as the sludge could have interfered with accurate speed readings, triggering the U0415:00:08 code and illuminating the warning lights. The test drive confirmed the functionality of the new sensor and the absence of further issues. The immediate reoccurrence of the code after the initial replacement and clearing may have been due to residual system memory or a brief learning period for the new component.
