Test J Pump Motor Circuit Test

J: Pump Motor Circuit Test:

ABS/TCS:

OPERATION:
^ When EBCM/EBTCM grounds terminal 15, the ABS pump relay is energized. The pump relay contacts close, applying voltage to the pressure modulator valve (PMV) assembly's pump motor. The EBCM/EBTCM turns on the pump motor during most ABS braking conditions and, when equipped, during all traction control conditions.
^ During most ABS braking conditions, the EBCM/EBTCM turns on the pump motor while monitoring the TCC/antilock brake switch to determine brake pedal position. The switch opens when the brake pedal is depressed approximately 40%. The motor restores the master cylinder's fluid pressure, causing the brake pedal to gradually rise. The pump motor continues to run until the brake pedal sufficiently rises to close the TCC/antilock brake switch.
^ During traction control mode (when equipped), after the front hydraulic brake circuits are isolated, the pump motor runs to increase brake fluid pressure in these circuits. The increased pressure is directed to the slipping wheel through the PMV assembly's front inlet and outlet valves. This causes the brakes to be applied, reducing wheel spin at the slipping wheel. Traction control is disabled as soon as the brakes are manually applied.
^ When the EBCM/EBTCM grounds terminal 15, DTC 61 sets when the EBCM/EBTCM determines that the voltage between EBCM/EBTCM terminals 31 and 49 is not between 500-800 mVAC. The EBCM/EBTCM recognizes this condition only during ABS braking requiring pump motor operation, traction control mode (when equipped), and during the EBCM/EBTCM self-check which occurs when the vehicle reaches 11 km/h (7 mph). Therefore, be sure to test drive vehicle; refer to "Test Drive", after clearing the diagnostic trouble code to assure correct diagnosis. Test Drive
^ DTC 61 also sets when the pump motor runs all the time (i.e., EBCM/EBTCM sees proper voltage between terminals 31 and 49 without grounding terminal 15).

POSSIBLE CAUSES:
- Open in CKT 1150, 864, 854, 1633, 1292, 1293, or 642.
- Short to ground in CKT 864, 854, 1292, 1293, or 642.
- ABS pump relay fails "open" or "engaged."