INJ-126 Kelsey Hayes

The Kelsey Hayes 4WAL systems used on many GM pickups are very unique in their operation and can be very expensive to fix.  This course covers differences in the system over the years and explains the systems in great detail.  A working Kelsey Hayes system will be used in class and be used for demonstration.  The student will also be shown how to disassemble a HCU in order to better understand the operation of the system and learn the details of proper brake bleeding procedures.  A detailed student manual is included.

Course Outline

  1. Introduction Introduction to course content
    • Simulator Familiarization
    • Review of RWAL
  2. Introduction of 4WAL on GM pickups
    • Application of EBC 4 
    • Application of EBC310
    • Explain the differences between the systems                 
  3. Identify and Describe
    • Warning Lamp Operation
    • 4WAL Components
    • Speed sensors
    • Digital ratio adapter      
    • Electro Hydraulic Control Unit
  4. Hydraulic Operation
    • Explain the operation of all components of the EHCU
    • PWM Valve
    • Reset Switch
    • Low Pressure Accumulator
    • High Pressure Accumulator
    • The Pump
  5. Describe the 4WAL
    • Perform Schematic Interpretation
    • Schematics
    • Analyze Inputs and Outputs
  6. Diagnosing, Repairing 4WAL Systems
  7. Code Retrieval and Diagnostics
  8. 4 Wheel Brake Bleeding Procedures
  9. Bulletins and Diagnostic Tips

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In Class


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Injectronics Training
50 McAuley Road Clandeboye, Manitoba R0C0P0
Phone: +1 (204) 228-8060