Automatic Transaxle Transmission External Controls - Transmission Control Switch (TCS): Notes
Overview
The transmission selector lever linkage consists of:
- a selector lever cable that connects the transmission manual control lever to the selector lever assembly.
- a BSIA that is integral to the selector lever assembly.
- a TCS that is integral to the selector lever knob and turns off the operation of 6th gear.
The selector lever assembly:
- locks the transmission selector lever in the PARK position when the ignition switch is in the LOCK position.
- requires the transmission selector lever to be in the PARK position to turn the ignition switch to the LOCK position.
System Operation
System Diagram
6F35 Only
| Item | Part Number | Description |
|---|---|---|
| 1 | - | Adjuster locking tab (part of 7E395) |
| 2 | 7B229 | Selector lever cable bracket |
| 3 | - | Selector lever cable grommet (part of 7E395) |
| 4 | 7E395 | Selector lever cable |
| 5 | 7210 | Selector lever assembly |
| 6 | - | TCS (part of 7213) |
| 7 | 7213 | Selector lever knob |
Range Selection
This transmission has 5 range positions: P, R, N, D and L.
Selector Lever - 6F35
In the park position:
- there is no power flow through the transmission.
- the parking pawl locks the final drive.
- the engine may be started.
- the ignition key may be removed.
Reverse
In the REVERSE position:
- the vehicle may be operated in a rearward direction, at a reduced gear ratio.
- engine braking will occur.
Neutral
In the NEUTRAL position:
- there is no power flow through the transmission.
- the output shaft is not held and is free to turn.
- the engine may be started.
Drive Position With Grade Assist
DRIVE is the normal position for most forward driving.
Drive provides:
- automatic shifts -1st through 6th gears.
- apply and release of the TCC.
- maximum fuel economy during normal operation.
Manual L Position
In the L position:
- the transmission provides maximum engine braking.
- the transmission downshifts to the lowest available gear for the current vehicle speed.
Manual L position allows for 1st gear when the vehicle reaches slower speeds.
Gear Availability
| Manual Lever Position | Transmission Gear Operation | Description |
|---|---|---|
| D Grade Assist | 1-2-3-4-5-6 | 1st through 5th gears are available. Transmission shifts to the 5th gear if the TCS button is pressed when the transmission is in 6th gear. Transmission provides engine braking. Grade assist is activated. |
| L | 1-2-3-4-6 | 1st gear hold with engine braking. The transmission downshifts to 1st gear when L is selected above a calibrated speed under minimum to moderate accelerator pedal position. |
Brake Shift Interlock
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-B, this allows the selector lever to be moved out of the PARK position.
| Inputs to BCM-B | Outputs from BCM-B |
|---|---|
| Fuse(s) 18 (10A) Brake Pedal Position (BPP) switch Ignition switch position (RUN/START) |
Brake Shift Interlock Actuator (BSIA) |
Proper Operation Requirements
Three requirements for the selector lever to be moved from the PARK position are:
- Ignition switch in the RUN/START position
- Transmission Range (TR) sensor in the PARK position
- Brake Pedal Position (BPP) switch closed (brakes applied - brake lamps on)
Transmission Control Switch (TCS)
Drive with Grade Assist - Transmission Control Switch (TCS)
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
- Improves vehicle handling in hilly terrain or mountainous areas by providing engine braking and extending lower gear operation on uphill climbs.
- 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).
- 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.