Antilock Brake System for Early Subarus:
Early model Subaru vehicles were fitted with either of two antilock braking systems. One is a Robert Bosch unit; the other is the ABS-2SL system from Nippon ABS, Limited. The third-generation antilock braking system was also manufactured for Subaru by Nippon ABS, Limited.
• four tone wheels
• four wheel speed sensors
• hydraulic control unit (HCU)
• electronic control unit (ECU)
• ABS warning light.
The HCU incorporates two relays, three solenoid valves, a mechanical valve and a fluid pump and motor. Note: The Service Manual refers to the solenoid valves in the HCU as “magnet valves.” We use “solenoid valve” because it is a name more commonly used in the U.S. market
Like its predecessors, ABS-2E is a four-sensor, four-channel system. However, it is smaller and lighter than the earlier designs. In addition, the ABS-2E system incorporates improvements in the areas of trouble code memory, self-diagnostics, inspection and maintenance.
The ABS-2E system appeared in production at the start of the 1993 model year and was available on the Legacy model if equipped with an automatic transmission. Also, early Impreza models equipped with ABS were fitted with the ABS-2E system.