Code 54 - Rear Channel Release Too Long: Notes

Detects if a motor is energized too long. This could occur if wheel speed sensor is defective, motor does not turn, rear solenoid is open or motor wires are crossed.

Code 54 can set only during ABS stop and EBCM/EBTCM commands left or right channel in release for 3 seconds. Code will be stored, ABS will be disabled and ABS warning light 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 54 Diagnostic Flow Chart

Courtesy of GENERAL MOTORS CORP.

Determines if a problem exists in wheel speed sensor that may cause system to be in release too long.
Confirms physical condition of rear brakes.
Checks if ABS motor is capable of moving and applying hydraulic piston for rear wheels.
Ensures ABS motor wiring is not crossed.
Isolates problem to either ABS motor pack or modulator assembly.