Electrical System: Notes

WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

This transmission is controlled by the PCM in gas engine applications or a standalone Transmission Control Module (TCM) in diesel engine applications. This transmission is controlled by 7 solenoids. To control the transmission, the PCM or TCM uses inputs from the Transmission Fluid Temperature (TFT), Transmission Range (TR), Turbine Shaft Speed (TSS) and Output Shaft Speed (OSS). The PCM or TCM also uses engine inputs from the High Speed Controller Area Network (HS-CAN) signal for gear and Torque Converter Clutch (TCC) scheduling and control.

Fig 1: Electrical System Communication Diagram

Courtesy of FORD MOTOR CO.

PCM INPUTS

Item	Affect	Description
Engine speed	Directly affects shift scheduling, Torque Converter Clutch (TCC) control, line pressure and transmission diagnostics. Indirectly affects shift pressure control.	Engine speed signal in rpm units, provided by the crankshaft position sensor
Engine torque estimate	Directly affects shift pressure control, TCC control and transmission diagnostics. Indirectly affects shift scheduling and TCC scheduling.	Engine torque estimate is based on engine load and is affected by several engine control sensors
Accelerator pedal position	Directly affects shift scheduling, TCC scheduling and transmission diagnostics. Indirectly affects TCC control and shift control.
Commanded engine torque	Directly affects shift scheduling, TCC scheduling and transmission diagnostics. Indirectly affects shift control.	Commanded engine torque is engine torque estimate in comparison to accelerator pedal position (driver input)
Brake pedal position	Directly affects shift scheduling and TCC scheduling

This transmission uses 2 types of solenoids, normally low and normally high. Normally low solenoids provide hydraulic pressure proportional to supplied current. A normally low solenoid will output very low pressure with low (50 mA) or no current, while it will supply high pressure with high current (850 mA). Normally high solenoids provide pressure inversely-proportional to supplied current. Normally high solenoids provide full output of pressure with low or no current (50 mA) and very low pressure with high current (850 mA).