Subaru Legacy 2004 Service Manual page 3018

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ABS (DIAGNOSTICS)
I: DTC C0115 ABS WHEEL SPEED SENSOR SIGNAL MALFUNCTION IN ONE
OF FOUR WHEELS
DTC DETECTING CONDITION:
• Defective ABS wheel speed sensor signal (noise, abnormal signal, etc.)
• Defective magnetic encoder
• When a wheel is turned freely for a long time
TROUBLE SYMPTOM:
• ABS does not operate.
• EBD does not operate.
NOTE:
Brake warning light comes on as well as ABS warning light.
ABS(diag)-51