DTC 48

DTC 44 & 48 Isolation Valve Circuit Open Or Shorted (part 1 Of 2):

DTC 44 & 48 Isolation Valve Circuit Open Or Shorted (part 2 Of 2 ):

Isolation Valve Circuit Open Or Shorted:

CIRCUIT OPERATION
Voltage is applied to the normally open isolation valves whenever the main relay is energized. An isolation valve closes when the EBTCM supplies a ground path at the isolation valve control terminal. The EBTCM closes an isolation valve when the EBTCM detects wheel slip in a drive wheel.

The isolation valves are closed only during traction control operations, and are not used during anti lock or normal braking conditions. The isolation valves separate (isolate) the front brake hydraulic circuits from the master cylinder and rear brake hydraulic circuits. Once the front brake hydraulic circuits are isolated, pressure can be applied to the front wheels without affecting any other brake hydraulic circuit. The EBTCM turns on the PMV motor to apply pressure, and begins cycling the PMV assembly inlet and outlet valves to modulate pressure.

FAILURE CONDITIONS
DTC 44 or DTC 48 sets when the EBTCM detects an open or short to ground in the respective isolation valve circuit.