Internal Cab Fault

NAME OF CODE:
Right Front Isolation Solenoid Shorted
Right Front Dump Solenoid Shorted
Left Front Isolation Solenoid Shorted
Left Front Dump Solenoid Shorted
Rear Isolation Solenoid Shorted
Rear Dump Solenoid Shorted

SET CONDITION:
1. Ignition key turned on for at least 3,4 seconds.
2. ASS power relay closed.
3. Valve command for a particular solenoid present.
4. High teed back voltage from low side of solenoid
5. Criteria 1 - 4 satisfied for over B consecutive controller checks spaced 5 ms apart.

THEORY OF OPERATION:
Vehicle battery voltage is applied to the high side of the six solenoid coils in the hydraulic assembly by the ABS power relay whenever valve activity may be required. Each solenoid is energized by turning on the CAB output driver transistor to short the low side of the coil to ground. Whenever a driver transistor is turned on, the feedback voltage should be low. If not, and the problem persists long enough to rule out noise input, the Solenoid Shorted code is set.

POSSIBLE CAUSES:
- Shorted solenoid
- Short to vehicle battery voltage or to 5-volt in the solenoid feedback to the CAB microprocessor
- Anything that keeps solenoid feedback voltage high when a particular solenoid is supposed to be energized

FIG. 1