N2 and N3 Speed Sensors
The N2 and N3 Input Speed Sensors are t wo H all-
effect speed sen sor s that are mount ed int erna lly in
the tra nsmission and ar e used by the TCM to ca lcu-
lat e the tra nsmission’s input speed. Since the input
speed cannot be mea su red direct ly, two of the dr ive
elements are mea su red. Two input speed sensors
were required because both drive elem ents a re n ot
active in all gears.
CAN C Bus Indirect Input Signals
A 2.5-volt bias (operatin g volta ge) is presen t on th e
CAN C bus an y time th e ignition switch is in th e
RUN position. Bot h the TCM and the ABS apply th is
bias. On t his vehicle, t he CAN C bus is used for mod-
ule data exchange only. The indirect input s used on
the NAG1 electronic control system a re:
• Wheel Speed Sensors.
• Br ake Switch.
• Engine RPM.
• Engine Temperature.
• Cr uise Control Stat us.
• Gea r Lim it Requ est .
• Th rottle Position - 0% at idle, 100% at WOT. If
open, TCM assumes idle (0% throttle opening).
• Odom eter Mileage
• Ma xim um Effective Torque.
• Engine in Limp-In Mode/Milea ge Wher e DTC
Wa s Set .
BRAKE TRANSMISSION SHIFT INTERLOCK (BTSI)
The BTSI solenoid prevent s shiftin g out of the
PARK position u ntil th e ignition key is in the RUN
position and the brake pedal is pressed. The TCM
controls the ground while th e ignition swit ch su pplies
power to t he BTSI solen oid. Th e PCM monitor s t he
brake switch a nd br oadcasts bra ke switch sta tus
messages over the CAN C bus. If the pa rk brake is
depr essed and there is power (Run/Start) to SLA, the
BTSI solenoid deactivates.
SHIFT SCHEDULES
The ba sic shift sch edule inclu des u p a nd down-
sh ifts for all five gear s. The TCM adapt s t he shift
pr ogram accordin g to driving style, accelerator pedal
position a nd deviation of vehicle speed. In fluen cing
factors a re:
• Roa d Conditions.
• Incline, Decline and Alt itu de.
• Tra iler Operat ion, Loading.
• Engine Coolan t Tempera tur e.
• Cr uise Control Opera tion .
• Sport y Driving Style.
• Low and H igh ATF Temperatur e.
Upshift
To:
1-2 2-3 3-4 4-5
Activat-
ed By
Sole-
noid:
1-2/4-5 2-3 3-4 1-2/4-5
Shift
Point
(at
35.2%
of throt-
tle)
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)
Down-
shift
From:
5-4 4-3 3-2 2-1
Activat-
ed By
Sole-
noid:
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 ar e not per formed if inad-
missible high engine rpm is sensed.
ADAPTATION
To equ alize tolera nces and wea r, an au tomatic
adapta tion takes place for :
• Shift Time.
• Clutch Filling Tim e.
• Clutch Filling Pressu re.
• Torque Converter Lock-Up Cont rol.
Ada pt ation data m ay be stored permanently an d to
som e ext ent, ca n be diagnosed.
Driving Style Adaptation
The shift point is modified in steps based on th e
information from t he inputs. The control module
looks at inputs su ch as:
• vehicle acceleration a nd deceler ation (calcu lated
by the TCM).
• rate of ch ange as well as the posit ion of the
throttle peda l (fuel injection information from the
ECM).
• lateral accelera tion (calcula ted by the TCM).
• gear change frequency (how often the shift
occurs).
Based on how a ggr essive the dr iver is, the TCM
moves up the shift so th at the present gear is h eld a
8E - 8 ELECTRONIC CONTROL MODULES VA
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