Automatic Transmission External Control - Transmission Control Switch: Overview Ford Explorer V

Overview

The transmission selector lever linkage consists of

1. a selector lever cable that connects the transmission manual control lever to the selector lever assembly.
2. a BSIA that is integral to the selector lever assembly.
3. a TCS that is integral to the selector lever knob and turns off the operation of 6th gear.

The selector lever assembly

1. locks the transmission selector lever in the PARK position when the ignition switch is in the LOCK position.
2. requires the transmission selector lever to be in the PARK position to turn the ignition switch to the LOCK position.

Scheme 34

Brake Shift Interlock Operation

When the ignition switch is in RUN/START, the solenoid inhibits the selector lever movement (from the PARK position) if the brake pedal is not pressed.

The BSIA inhibits the selector lever movement from the PARK position by mechanically blocking the detent pawl of the selector lever mechanism. When the brake pedal is applied with the ignition key in the RUN/START position and the transmission in PARK, the BSIA is energized by the BCM , this allows the selector lever to be moved out of the PARK position.

Proper Operation Requirements

Three requirements for the selector lever to be moved from the PARK position are

1. Ignition switch in the RUN/START position
2. TR sensor in the PARK position
3. BPP switch closed (brakes applied - brake lamps on)

Scheme 35

Drive with grade assist is activated when the TCS is pressed. The TCS is located on the selector lever knob. When the TCS is pressed, the 6th gear or O/D upshift is prevented or the transmission shifts down to 5th gear. The TCS is meant to be used when driving conditions cause excessive shifting from 6th to other gears such as hilly terrain, mountainous areas or when engine braking is required.

Grade Assist

1. Improves vehicle handling in hilly terrain or mountainous areas by providing engine braking and extending lower gear operation on uphill climbs.
2. Additional engine braking is provided through the automatic transmission shift strategy which reacts to vehicle inputs (vehicle acceleration, accelerator pedal, brake pedal and vehicle speed).
3. The transmission will select gears that will provide the engine braking desired, based on the vehicle inputs, this will increase engine rpm during engine braking.

It is recommended to return to DRIVE mode on flat terrain to provide the best fuel economy and transmission function. The transmission returns to O/D when the TCS is pressed again or anytime the key is turned OFF.

Normal Operation and Fault Conditions

The TCS is a momentary contact switch located on the selector lever. Pressing the TCS will engage or disengage the O/D function of the transmission. When the O/D is disengaged, the O/D icon will illuminate OFF on the IPC. Each time the ignition switch is cycled, the transmission will automatically provide O/D operation regardless of TCS position the last time the engine was running.

DTC FAULT TRIGGER CONDITIONS

The BSIA system is controlled by the BCM and is activated when the BCM receives a brake pedal applied input.

DTC FAULT TRIGGER CONDITIONS

The BSIA system is controlled by the BCM and is activated when the BCM receives a brake pedal applied input.

DTC FAULT TRIGGER CONDITIONS