K 2500 Truck 4WD V8-6.5L DSL Turbo VIN S (1998)
2-3 SHIFT SOLENOID VALVE
The 2-3 Shift Solenoid valve is attached to the valve body and is a normally open exhaust valve. The VCM/PCM activates the valve by grounding the
valve through an internal quad driver. The 2-3 Shift Solenoid is ON in third and Fourth gear and OFF in First and Second gear. When ON, the valve
redirects fluid to act on the shift valve. The 2-3 Shift Solenoid valve is usually white.
Two diagnostic codes are associated with the 2-3 Shift Solenoid valve: P0758 and P0756.
The first code is Code P0758 (2-3 Shift Solenoid Valve-electrical). The VCM/PCM continually monitors the 2-3 Shift Solenoid circuit for expected
voltage. If the voltage reading is not what is expected, Code P0758 will set. While Code P0758 is present, TCC operation will be inhibited, line
pressure will be set to maximum, and the transmission will default to Second gear only. Recovery can occur at the next ignition cycle.
Code P0756 (2-3 Shift Solenoid Valve-performance) will set when the calculated gear ratio is numerically higher than the gear commanded, which
must be either Third or Fourth gear. The VCM/PCM default action is Second gear only.
