DTC 61

Fig. 149 Code 61: Pump Motor Or Pump Motor Relay Fault (Part 1 Of 3).:

Code 61: Pump Motor Or Pump Motor Relay Fault (part 2 Of 3).:

Fig. 149 Code 61: Pump Motor Or Pump Motor Relay Fault (part 3 Of 3).:

DTC 61: Pump Motor Or Pump Motor Relay Fault:

CIRCUIT DESCRIPTION
The pump motor returns brake fluid to the master cylinder brake circuit at the BPM Valve during antilock braking and provides brake fluid pressure to the front wheels during traction control. During normal braking, the pump does not operate. When the vehicle begins to move after start-up, the EBTCM/EBCM will turn on the pump motor and perform a self-check of the pump motor and pump motor circuit. This check may be felt and heard by the driver when the vehicle begins to move. The self-check should be considered normal operation. The pump motor is an integral component of the BPM Valve and cannot be serviced separately.

The pump motor relay provides power to the pump motor in the BPM Valve. The pump motor relay is located on the BPM Valve and may be replaced if it is found to be defective.

The pump motor relay is not engaged during normal system operation. When antilock or traction control operation is required, the motor relay actuation line on CKT 874 (EBTCM/EBCM pin "28") is pulled to ground. The pump motor relay is engaged by the relay supply voltage line on CKT 854 (EBTCM/EBCM pin "17"). When the relay switches, battery power is provided to the pump motor.

TEST CONDITION(S)
1. Tested continuously.

FAILURE CONDITION(S)
1. Drive Away: Motor voltage is not detected during first drive away after engine start.
2. While Driving: Motor relay is energized and motor voltage is not detected.
3. Voltage at EBTCM/EBCM pin "14" below 9 volts.
4. Pump runs continuously.

ACTION TAKEN
1. Code set.
2. ABS/TCS switched "OFF."
3. "ANTILOCK" indicator "ON."
4. "TRACTION DISABLED" message displayed. (vehicles with TCS)

When the pump motor relay is engaged, the motor monitor line should be at battery voltage. With the pump motor relay disengaged, the monitoring line should be at ground. If the commanded position of the pump motor relay and motor monitor line do not agree, Code 61 will set. Some conditions which will cause Code 61 to set are:
^ An open circuit on CKTs 874 or 1292.
^ A short to voltage on CKTs 874 or 1292.
^ A short to ground on CKTs 874 or 1292.
^ A defective pump motor relay or pump motor.

TEST DESCRIPTION
Test numbers refer to circled numbers on the diagnostic chart.
1. Checks the pump motor relay coil for proper resistance.
2. Determines if the pump motor relay contacts are stuck closed.
3. Determines if the pump motor relay contacts are stuck open.
4. Checks for an open in power feed CKT 1042.
5. Checks the integrity of the pump motor and pump motor relay circuitry internal to the BPM valve.
6. Checks for a good ground to the BPM valve (CKT 250).
7. Checks for an open in CKT 1292.
8. Checks for a short to ground in CKT 1292.
9. Checks for a short to system voltage in CKT 1292.
10. Checks for an open in CKT 874.
11. Checks for a short to ground on CKT 874.
12. Checks for a short to B+ in CKT 874.
13. Checks wiring and connectors for intermittents.
14. Uses the TECH 1 to check for proper operation of the pump motor and associated circuitry.
15. Determines whether the problem found in Step 13 was due to faulty EBTCM/EBCM or BPM valve.

DIAGNOSTIC AIDS
All tests using J 39700 Universal Breakout Box terminal "20" are using the terminal as ground. These tests, of course, assume that the ground CKT 1250 at terminal "20" is good.

It is very important that a through inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the fault.