Test X Isolation Valve Continuity Test

X: Isolation Valve Continuity Test:

ABS/TCS:

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

POSSIBLE CAUSES:
- Open in CKT 1633, 1657, or 1658.
- Short to ground in CKT 1657 or 1658.
- Faulty pressure modulator valve (PMV) assembly.