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 used to diagnose automatic transmission shift problems.
The chart reveals that activating shift solenoid A causes the transmission to shift into the 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 clutch and band charts help a technician quickly interpret which solenoids and friction devices are activated for each gear. Through elimination, a technician can determine if it's electrical or mechanical.