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