to confirm switch status. The PCM receives this
information and allows operation of the starter cir-
cuit.
N2 and N3 Speed Sensors
The N2 and N3 Input Speed Sensors are two Hall-
effect speed sensors that are used by the TCM to cal-
culate the transmissions input speed. Since the input
speed cannot be measured directly, two of the drive
elements are measured. Two input speed sensors
were required because both drive elements are not
active in all gears.
CAN C Bus Indirect Input Signals
A 2.5-volt bias (operating voltage) is present on the
CAN C bus any time the ignition switch is in the
RUN position. Both the TCM and the ABS apply this
bias. On this vehicle, the CAN C bus is used for mod-
ule data exchange only. The indirect inputs used on
the W5J400 electronic control system are:
• Wheel Speed Sensors.
• Transfer Case Switch Status.
• Brake Switch.
• Engine RPM.
• Engine Temperature.
• Cruise Control Status.
• Gear Limit Request.
• Throttle Position - 0% at idle, 100% at WOT. If
open, TCM assumes idle (0% throttle opening).
• Odometer Mileage
• Maximum Effective Torque.
• Engine in Limp-In Mode/Mileage Where DTC
Was Set.
• Engine Torque Reduction Request.
BRAKE TRANSMISSION SHIFT INTERLOCK (BTSI)
The BTSI solenoid prevents shifting out of the
PARK position until the ignition key is in the RUN
position and the brake pedal is pressed. The TCM
controls the ground while the ignition switch supplies
power to the BTSI solenoid. The PCM monitors the
brake switch and broadcasts brake switch status
messages over the CAN C bus. If the park brake is
depressed and there is power (Run/Start) to SLSA,
the BTSI solenoid deactivates. The TCM monitors
this for the SLSA because the SLSA does not commu-
nicate on the CAN C bus.
SHIFT SCHEDULES
The basic shift schedule includes up and down-
shifts for all five gears. The TCM adapts the shift
program according to driving style, accelerator pedal
position and deviation of vehicle speed. Influencing
factors are:
• Road Conditions.
• Incline, Decline and Altitude.
• Trailer Operation, Loading.
• Engine Coolant Temperature.
• Cruise Control Operation.
• Sporty Driving Style.
• Low and High ATF Temperature.
Upshift
To:
1-2 2-3 3-4 4-5
Activated
By
Solenoid:
1-2/4-5 2-3 3-4 1-2/4-5
Shift
Point (at
35.2% of
throttle)
17.8
km/h
(11.6
mph)
32.1
km/h
(19.95
mph)
67.5
km/h
(41.94
mph)
73.8
km/h
(45.86
mph)
Downshift
From:
5-4 4-3 3-2 2-1
Activated
By
Solenoid:
1-2/4-5 3-4 2-3 1-2/4-5
Shift
Point
55.7
km/h
(34.61
mph)
40.5
km/h
(25.17
mph)
24.4
km/h
(15.16
mph)
15.1
km/h
(9.38
mph)
DOWNSHIFT SAFETY
Selector lever downshifts are not performed if inad-
missible high engine rpm is sensed.
ENGINE MANAGEMENT INTERVENTION
By briefly retarding the ignition timing during the
shifting process, engine torque is reduced and there-
fore, shift quality is optimized.
ADAPTATION
To equalize tolerances and wear, an automatic
adaptation takes place for:
• Shift Time.
• Clutch Filling Time.
• Clutch Filling Pressure.
• Torque Converter Lock-Up Control.
Adaptation data may be stored permanently and to
some extent, can be diagnosed.
Driving Style Adaptation
The shift point is modified in steps based on the
information from the inputs. The control module
looks at inputs such as:
• vehicle acceleration and deceleration (calculated
by the TCM).
• rate of change as well as the position of the
throttle pedal (fuel injection information from the
PCM).
8Ea - 6 ELECTRONIC CONTROL MODULES WG
TRANSMISSION CONTROL MODULE (Continued)
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