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Code 44/45/46 - Channel (Motor) Will Not Move: Notes

Detects bound-up Expansion Spring Brake (ESB), a stuck ABS motor or a seized hydraulic modulator. When ESB release is commanded by EBCM/EBTCM during initialization, ESB should release ABS motor, resulting in sensed current being less than commanded current (motor free-spinning). If ABS motor is not moving, sensed current will be equal to stall current.

Codes 44/45/46 can set during normal operation and EBCM/EBTCM detects a condition in which it cannot move ABS motor in either direction. Code will be stored, ABS will be disabled and ABS warning light illuminated.

NOTE: Test numbers refer to numbers on diagnostic chart. Use only 10-megohm (minimum) DVOM for all voltage and resistance tests. For identification of circuits and terminals referenced in charts and text, see WIRING DIAGRAM  .
Fig 1: Code 44/45/46 Diagnostic Flow Chart
G95C15679Courtesy of GENERAL MOTORS CORP.
  1. Checks if motor terminals are in proper connector cavities.
  2. Checks for proper motor movement during apply and release command from Tech 1 scan tool.
  3. Compares command and feedback current.
  4. Checks for short between ABS motor high and low circuit.
  5. Checks for internally shorted ABS motor.
  6. Determines if malfunction is due to poor terminal contact or EBCM/EBTCM.
  7. Verifies if ABS motor can release when commanded.
  8. Checks for proper hydraulic modulator gear and piston movement.