Electronic System Description: Notes

WARNING: This page is about a different car, the 2005 Ford RV Cutaway, 2005 Ford Econoline, 2005 Ford E450 Super Duty, and 2005 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

Transmission shift scheduling relies on the following:

Accelerator pedal position
Engine speed and acceleration
Vehicle speed and acceleration
Engine torque
Converter state as defined by engine speed
Turbine speed
Transmission range sensor position
Brake status
Speed control status
Transmission fluid temperature
Engine coolant temperature

The powertrain control module (PCM) and its input/output network control the following transmission operations:

VFS (shift feel)
Shift timing
Line pressure (engagement feel)
Torque converter clutch operation

The transmission control is separate from the engine control strategy in the PCM, although some of the input signals are shared. When determining the best operating strategy for transmission operation, the PCM uses input information from certain engine-related and driver demand-related sensors and switches.

The following components are used to determine engine torque information for the transmission control strategies:

Crankshaft position (CKP) sensor
Camshaft position (CMP) sensor
Barometric pressure (BARO) sensor
Mass air flow (MAF) sensor
Manifold absolute pressure (MAP) sensor
Engine oil temperature (EOT) sensor
Air conditioning pressure (ACP) switch
Exhaust gas recirculation (EGR) valve
Injection pressure regulator (IPR)
Manifold air temperature (MAT) sensor

Any concerns with the engine sensors must be diagnosed and repaired before proceeding with diagnosis of the transmission components. See INTRODUCTION - GASOLINE and/or INTRODUCTION -- 6.0L DIESEL articles for engine component diagnosis.

Using all of these input signals, the PCM can determine when the time and conditions are right for a shift, or when to apply or release the torque converter clutch. It will also determine the best line pressure needed to optimize shift feel. To accomplish this, the PCM uses output solenoids to control transmission operation.

The following provides a brief description of each of the sensors and actuators used by the PCM for transmission operation.