Code 47/48/51 - Abs Motor Free Spins: Notes

Code 47 - Left Front Motor
Code 48 - Right Front Motor
Code 51 - Rear Motor

Detects a stripped nut/screw or gear assembly during initialization. During homing sequence, piston should reach top of bore resulting in ABS motor stalling. If this does not occur, motor must be spinning with little or no resistance, indicating a nut/screw or gear malfunction.

Codes 47/48/51 can set only during initialization, if feedback current is less than command current for a specified period of time. Code will be stored, ABS will be disabled and ABS warning light will be 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 47/48/51 Diagnostic Flow Chart - 1 Of 2

Courtesy of GENERAL MOTORS CORP.

Checks if corresponding open motor Code 56, 61 or 64 is also present.
Verifies that ABS motor was applied by monitoring feedback current.
Verifies that ABS motor can release.
Verifies that ABS motor can be applied by monitoring pedal movement.
Checks for high resistance in ABS motor high circuit.
Checks for high resistance in ABS motor low circuit.
Checks for proper resistance in ABS motor windings.