Solenoid Application Charts
Transmission solenoids are electro-hydraulic actuators that the TCM uses to control the flow of pressurized transmission fluid throughout the transmission. The solenoid application chart below is a tool used to diagnose automatic transmission shift problems.
The chart reveals that activating shift solenoid A causes the transmission to shift into first and fourth gears. The TCM powers solenoid B to shift into first and second.
It contains two shift valves, A and B, that provide four different shift valve combinations. The TCM powers both solenoids for first, solenoid B for second gear, neither for third, and solenoid A for fourth.
Solenoid or a clutch and band charts help a technician quickly interpret which solenoids and friction devices are activated for each gear. Through a process of elimination, a technician can determine if it's electrical or mechanical.