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Home >> Buick >> 1993 >> Roadmaster Base >> Repair and Diagnosis >> Brakes >> Traction Control >> Anti-Lock Brake System - BOSCH 2U >> Diagnostic Code Charts >> Code 61 - Pump Motor Or Relay Fault

Code 61 - Pump Motor Or Relay Fault

Pump motor returns brake fluid to master cylinder brake circuit at brake pressure modulator during anti-lock braking. During normal braking, pump does not operate. When vehicle begins to move after start-up, EBCM will turn on pump motor and perform a self-check of pump motor and pump motor circuit. This check may be felt and heard by the driver when vehicle begins to move and is considered part of normal operation. Pump motor is an integral part of brake pressure modulator and cannot be serviced separately.

Pump motor relay provides power to pump motor. Voltage to motor relay is supplied from circuit No. 1079 (pin No. 17). Motor relay is grounded through circuit No. 854.

Code 61 will set if battery voltage is present at pump motor without pump motor being requested to activate or if battery voltage is not present at pump motor within 60 milliseconds after pump motor has been requested to activate.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. Checks resistance of relay coil.
  2. Checks if relay contacts are stuck closed.
  3. Checks if relay contacts are stuck open.
  4. Checks integrity of brake pressure modulator internal circuit.
  5. Checks for an open in pump ON input circuit.
  6. Checks for open in pump motor relay coil (switched ground circuit).
  7. Checks for short to ground in pump ON input circuit.
  8. Checks for short to ground in pump motor relay coil (switched ground Circuit).
  9. Checks for short to voltage in pump ON input circuit.
  10. Checks for short to voltage in pump motor relay coil (switched ground circuit).
  11. Checks for an open in brake pressure modulator battery feed circuit.
  12. Checks for poor connections which may have set a code.
  13. Checks if pump motor is operating.
  14. Checks for a false code being set.
  15. Checks for a good pump motor ground circuit.
Fig 1: Code 61 - Schematic
G92H04935Courtesy of GENERAL MOTORS CORP.
Fig 2: Code 61 - Diagnostic Flowchart (1 Of 2)
G93H41837Courtesy of GENERAL MOTORS CORP.
Fig 3: Code 61 - Diagnostic Flowchart (2 Of 2)
G93I41838Courtesy of GENERAL MOTORS CORP.