transmission relay JEEP GRAND CHEROKEE 2002 WJ / 2.G Owner's Guide

8W-54 TRAILER TOW
Component Page
Body Control Module................. 8W-54-2
Brake Lamp Switch................ 8W-54-3, 5
Cigar Lighter Relay.................. 8W-54-4
Circuit Breaker...................... 8W-54-4
Combination Flasher................. 8W-54-5
Electric Brake..................... 8W-54-3, 5
Fuse 6............................. 8W-54-2
Fuse 18............................ 8W-54-5
Fuse 23............................ 8W-54-3
G200.............................. 8W-54-2
G300.............................. 8W-54-3Component Page
G301.............................. 8W-54-5
Junction Block................ 8W-54-2, 3, 4, 5
Park Lamp Relay.................... 8W-54-2
Park/Neutral Position Switch........... 8W-54-4
Trailer Tow Brake Lamp Relay...... 8W-54-3, 5, 6
Trailer Tow Circuit Breaker............ 8W-54-4
Trailer Tow Connector........... 8W-54-2, 3, 4, 6
Trailer Tow Left Turn Relay.......... 8W-54-5, 6
Trailer Tow Right Turn Relay......... 8W-54-5, 6
Transmission Solenoid/TRS Assembly..... 8W-54-4
WJ8W-54 TRAILER TOW 8W - 54 - 1

Component Page
RIGHT FRONT WHEEL SPEED
SENSOR....................... 8W-80-115
RIGHT HEADLAMP LEVELING MOTOR
(BUILT-UP-EXPORT)............. 8W-80-115
RIGHT HIGH BEAM HEADLAMP..... 8W-80-116
RIGHT INSTRUMENT PANEL
SPEAKER...................... 8W-80-116
RIGHT LIFTGATE AJAR SWITCH..... 8W-80-116
RIGHT LOW BEAM HEADLAMP..... 8W-80-116
RIGHT MULTI-FUNCTION SWITCH . . . 8W-80-116
RIGHT REAR DOOR LOCK
MOTOR/AJAR SWITCH........... 8W-80-117
RIGHT REAR DOOR SPEAKER....... 8W-80-117
RIGHT REAR LAMP ASSEMBLY...... 8W-80-117
RIGHT REAR WHEEL SPEED
SENSOR....................... 8W-80-117
RIGHT REMOTE RADIO SWITCH.... 8W-80-117
RIGHT SIDE REPEATER LAMP
(BUILT-UP-EXPORT)............. 8W-80-118
RIGHT VISOR/VANITY LAMP........ 8W-80-118
SEAT BELT SWITCH............... 8W-80-118
SEAT MODULE C1 (PREMIUM)...... 8W-80-118
SEAT MODULE C2 (PREMIUM)...... 8W-80-119
SENTRY KEY IMMOBILIZER
MODULE...................... 8W-80-119
SHIFTER ASSEMBLY
(C201 DIESEL).................. 8W-80-119
SHIFTER ASSEMBLY (GAS)......... 8W-80-120
SHIFTER ASSEMBLY C1 (DIESEL).... 8W-80-120
SHIFTER ASSEMBLY C2 (DIESEL).... 8W-80-120
SIREN (BUILT-UP-EXPORT)......... 8W-80-120
SPEED CONTROL SWITCH NO. 1.... 8W-80-120
SPEED CONTROL SWITCH NO. 2.... 8W-80-121
SUNROOF CONTROL MODULE...... 8W-80-121
SUNROOF MOTOR C1.............. 8W-80-121
SUNROOF MOTOR C2.............. 8W-80-121
SUNROOF SWITCH................ 8W-80-121Component Page
TEMPERATURE VALVE
ACTUATOR (MTC)............... 8W-80-122
THROTTLE POSITION
SENSOR (4.0L).................. 8W-80-122
THROTTLE POSITION
SENSOR (4.7L).................. 8W-80-122
TRAILER TOW BRAKE
LAMP RELAY................... 8W-80-122
TRAILER TOW CIRCUIT
BREAKER...................... 8W-80-122
TRAILER TOW CONNECTOR........ 8W-80-123
TRAILER TOW LEFT TURN
RELAY........................ 8W-80-123
TRAILER TOW RIGHT TURN
RELAY........................ 8W-80-123
TRANSFER CASE POSITION
SENSOR....................... 8W-80-123
TRANSMISSION CONTROL
MODULE (4.7L)................. 8W-80-124
TRANSMISSION CONTROL
MODULE C1 (DIESEL)........... 8W-80-125
TRANSMISSION CONTROL
MODULE C2 (DIESEL)........... 8W-80-125
TRANSMISSION SOLENOID (4.0L).... 8W-80-125
TRANSMISSION SOLENOID
ASSEMBLY (DIESEL)............ 8W-80-126
TRANSMISSION SOLENOID/TRS
ASSEMBLY (4.7L)................ 8W-80-126
UNDERHOOD LAMP............... 8W-80-126
VEHICLE INFORMATION CENTER . . . 8W-80-127
VISCOUS/CABIN HEATER
(DIESEL)...................... 8W-80-127
WASHER FLUID LEVEL SWITCH.... 8W-80-127
WASTEGATE SOLENOID
(DIESEL)...................... 8W-80-127
WATER IN FUEL SENSOR
(DIESEL)...................... 8W-80-127
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 5

POWERTRAIN CONTROL MODULE C2 (GAS) - WHITE 32 WAY
CAV CIRCUIT FUNCTION
1 T54 18VT (4.0L) TRANSMISSION TEMPERATURE SENSOR SIGNAL
2 K26 18VT (4.7L) FUEL INJECTOR NO. 7 DRIVER
3- -
4 K11 18WT/DB FUEL INJECTOR NO. 1 DRIVER
5 K13 18YL/WT FUEL INJECTOR NO. 3 DRIVER
6 K38 18GY FUEL INJECTOR NO. 5 DRIVER
7 K97 14BR (4.7L) COIL DRIVER NO. 7
8 K88 18PK (4.0L) GOVERNOR PRESSURE SOLENOID CONTROL
9 K92 14TN/PK COIL DRIVER NO. 2
10 K20 18DG GENERATOR FIELD DRIVER
11 T20 18LB (4.0L) TORQUE CONVERTER CLUTCH SOLENOID CONTROL
12 K58 18BR/DB FUEL INJECTOR NO. 6 DRIVER
13 K28 18GY/LB (4.7L) FUEL INJECTOR NO. 8 DRIVER
14 - -
15 K12 18TN FUEL INJECTOR NO. 2 DRIVER
16 K14 18LB/BR FUEL INJECTOR NO. 4 DRIVER
17 K173 18LG RADIATOR FAN RELAY CONTROL
18 - -
19 C18 18DB A/C PRESSURE SIGNAL
20 - -
21 T60 18BR (4.0L) 3-4 SHIFT SOLENOID CONTROL
22 - -
23 G60 18GY/YL ENGINE OIL PRESSURE SENSOR SIGNAL
24 - -
25 T13 18DB/BK (4.0L) SPEED SENSOR GROUND
26 - -
27 B22 18DG/YL VEHICLE SPEED SENSOR SIGNAL
28 T14 18LG/WT (4.0L) OUTPUT SPEED SENSOR SIGNAL
29 T25 18LG/RD (4.0L) GOVERNOR PRESSURE SENSOR SIGNAL
30 K30 18PK/YL (4.0L) TRANSMISSION CONTROL RELAY CONTROL
31 K6 18VT/BK 5 VOLT SUPPLY
32 - -
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 109

TRANSMISSION CONTROL MODULE (4.7L) - BLACK 60 WAY
CAV CIRCUIT FUNCTION
1 T1 18LG/BK TRS T1 SENSE
2 T2 18TN/BK TRS T2 SENSE
3 T3 18VT TRS T3 SENSE
4- -
5- -
6 K24 18GY/BK CRANKSHAFT POSITION SENSOR SIGNAL
7 D21 18PK SCI TRANSMIT
8 F45 18YL/RD FUSED IGNITION SWITCH OUTPUT (START)
9 T9 18OR/BK OVERDRIVE PRESSURE SWITCH SENSE
10 T10 18YL/DG TORQUE MANAGEMENT REQUEST SENSE
11 F991 18OR/DB FUSED IGNITION SWITCH OUTPUT (RUN-START)
12 K22 18OR/RD THROTTLE POSITION SENSOR SIGNAL
13 T13 18DB/BK SPEED SENSOR GROUND
14 T14 18LG/WT OUTPUT SPEED SENSOR SIGNAL
15 K30 18PK/YL TRANSMISSION CONTROL RELAY CONTROL
16 T16 14RD TRANSMISSION CONTROL RELAY OUTPUT
17 T16 14RD TRANSMISSION CONTROL RELAY OUTPUT
18 T118 18YL/DB PRESSURE CONTROL SOLENOID CONTROL
19 T119 18WT/DB 2C SOLENOID CONTROL
20 T120 18LG LR SOLENOID CONTROL
21 - -
22 - -
23 - -
24 - -
25 - -
26 - -
27 - -
28 - -
29 T29 18GY UNDERDRIVE PRESSURE SWITCH SENSE
30 T130 14VT/TN LINE PRESSURE SENSOR SIGNAL
31 - -
32 - -
33 - -
34 - -
35 - -
36 T16 14RD TRANSMISSION CONTROL RELAY OUTPUT
37 Z113 14BK/WT GROUND
38 T138 14GY/LB 5 VOLT SUPPLY
39 Z112 14BK/YL GROUND
40 T140 18VT/LG MS SOLENOID CONTROL
41 T41 18WT TRS T41 SENSE
42 T42 18VT/WT TRS T42 SENSE
43 D25 18YL/VT PCI BUS
44 - -
45 - -
46 D20 18LG SCI RECEIVE
47 T147 18LB 2C PRESSURE SWITCH SENSE
48 T48 18DB 4C PRESSURE SWITCH SENSE
49 T6 18VT/WT OVERDRIVE OFF SWITCH SENSE
50 T150 18BR/LB LR PRESSURE SWITCH SENSE
51 K4 18BK/LB SENSOR GROUND
52 T52 18RD/BK INPUT SPEED SENSOR SIGNAL
53 Z114 14BK/LG GROUND
54 T54 18VT TRANSMISSION TEMPERATURE SENSOR SIGNAL
55 T59 18PK UNDERDRIVE SOLENOID CONTROL
56 A30 14RD/WT FUSED B(+)
57 Z12 14BK/TN GROUND
58 - -
59 T159 18DG/WT 4C SOLENOID CONTROL
60 T60 18BR OVERDRIVE SOLENOID CONTROL
8W - 80 - 124 8W-80 CONNECTOR PIN-OUTWJ

TRANSMISSION CONTROL MODULE C1 (DIESEL) - BLACK 18 WAY
CAV CIRCUIT FUNCTION
1 D21 20PK SCI TRANSMIT
2- -
3 W4 20PK/OR SHIFTER C5 SENSE
4 Y1 20DB/PK PARK LOCKOUT SOLENOID CONTROL
5- -
6- -
7 T41 20BK/WT PARK/NEUTRAL POSITION SWITCH SENSE (T41)
8- -
9- -
10 - -
23 - -
24 - -
25 W0 20DB/WT SHIFTER C1 SENSE
26 W1 20VT/WT SHIFTER C2 SENSE
27 W2 20VT SHIFTER C3 SENSE
28 W3 20BK SHIFTER C4 SENSE
29 F991 20OR/DB FUSED IGNITION SWITCH OUTPUT (RUN-START)
30 Z234 20WT GROUND
TRANSMISSION CONTROL MODULE C2 (DIESEL) - BLACK 14 WAY
CAV CIRCUIT FUNCTION
12 T52 18RD/BK N2 INPUT SPEED SENSOR
13 T39 18GY/LB SENSOR SUPPLY VOLTAGE
14 T60 18BR 1-2/4-5 SOLENOID CONTROL
15 T159 18DG/WT 3-4 SOLENOID CONTROL
16 T119 18WT/DB 2-3 SOLENOID CONTROL
17 T120 18LG TCC SOLENOID CONTROL
33 T13 18DB/BK SENSOR GROUND
34 T54 18VT TEMP SENSOR - P/N SWITCH
35 T14 18LG/WT N3 INPUT SPEED SENSOR
36 T591 18YL/DB MODULATION PRESSURE SOLENOID CONTROL
37 T118 18YL/DB SHIFT PRESSURE SOLENOID CONTROL
38 T16 18RD SOLENOID SUPPLY VOLTAGE
H1 D52 18LG/WT CAN C BUS(+)
L2 D51 18DG/WT CAN C BUS(-)
TRANSMISSION SOLENOID (4.0L) - BLACK 8 WAY
CAV CIRCUIT FUNCTION
1 T15 18LG FUSED TRANSMISSION CONTROL RELAY OUTPUT
2 K6 18VT/BK 5 VOLT SUPPLY
3 K4 18BK/LB SENSOR GROUND
4 T25 18LG/RD GOVERNOR PRESSURE SENSOR SIGNAL
5 K88 18PK GOVERNOR PRESSURE SOLENOID CONTROL
6 T60 18BR 3-4 SHIFT SOLENOID CONTROL
7 T20 18LB TORQUE CONVERTER CLUTCH SOLENOID CONTROL
8 T54 18VT TRANSMISSION TEMPERATURE SENSOR SIGNAL
WJ8W-80 CONNECTOR PIN-OUT 8W - 80 - 125

TRANSMISSION SOLENOID ASSEMBLY (DIESEL) - BLACK 13 WAY
CAV CIRCUIT FUNCTION
1 T14 18LG/WT N3 INPUT SPED SENSOR
2 T591 18YL/DB MODULATION PRESSURE SOLENOID CONTROL
3 T52 18RD/BK N2 INPUT SPEED SENSOR
4 T54 18VT TEMP SENSOR - P/N SWITCH
5- -
6 T16 18RD SOLENOID SUPPLY VOLTAGE
7 T39 18GY/LB SENSOR SUPPLY VOLTAGE
8 T119 18WT/DB 2-3 SOLENOID CONTROL
9 T159 18DG/WT 3-4 SOLENOID CONTROL
10 T118 18YL/DB SHIFT PRESSURE SOLENOID CONTROL
11 T120 18LG TCC SOLENOID CONTROL
12 T13 18DB/BK SENSOR GROUND
13 T60 18BR 1-2/4-5 SOLENOID CONTROL
TRANSMISSION SOLENOID/TRS ASSEMBLY (4.7L) - GRAY 23 WAY
CAV CIRCUIT FUNCTION
1 F22 18WT/PK FUSED IGNITION SWITCH OUTPUT (RUN)
2 T120 18LG LR SOLENOID CONTROL
3 T41 18BK/WT PARK/NEUTRAL POSITION SWITCH SENSE (T41)
4 T141 18WT TRS T41 SENSE
5 T42 18VT/WT TRS T42 SENSE
6 L1 18VT/BK BACK-UP LAMP FEED
7 T60 18BR OVERDRIVE SOLENOID CONTROL
8 T3 18VT TRS T3 SENSE
9 T1 18LG/BK TRS T1 SENSE
10 T16 14RD TRANSMISSION CONTROL RELAY OUTPUT
11 T48 18DB 4C PRESSURE SWITCH SENSE
12 T118 18YL/DB PRESSURE CONTROL SOLENOID CONTROL
13 T2 18TN/BK TRS T2 SENSE
14 T150 18BR/LB LR PRESSURE SWITCH SENSE
15 T147 18LB 2C PRESSURE SWITCH SENSE
16 T9 18OR/BK OVERDRIVE PRESSURE SWITCH SENSE
17 T59 18PK UNDERDRIVE SOLENOID CONTROL
18 T29 18GY UNDERDRIVE PRESSURE SWITCH SENSE
19 T159 18DG/WT 4C SOLENOID CONTROL
20 T119 18WT/DB 2C SOLENOID CONTROL
21 T140 18VT/LG MS SOLENOID CONTROL
22 T13 18DB/BK SPEED SENSOR GROUND
23 T54 18VT TRANSMISSION TEMPERATURE SENSOR SIGNAL
UNDERHOOD LAMP - BLACK 2 WAY
CAV CIRCUIT FUNCTION
1 Z141 20BK GROUND
2 M1 20PK/RD FUSED B(+)
8W - 80 - 126 8W-80 CONNECTOR PIN-OUTWJ

CONNECTOR NAME/
NUMBERCOLOR LOCATION FIG.
Trailer Tow Brake Lamp Relay BK Left Quarter Panel N/S
Trailer Tow Circuit Breaker BK Left Quarter Panel N/S
Trailer Tow Connector BK In Rear Bumper 39
Trailer Tow Left Turn Relay BK Left Quarter Panel N/S
Trailer Tow Right Turn Relay BK Left Quarter Panel N/S
Transfer Case Position Sensor BK On Transfer Case 7
Transmission Control Module
(4.7L)BK Rear of Engine Compartment 14, 15, 18
Transmission Control Module
C1 (Diesel)BK Right Rear Side of Engine
CompartmentN/S
Transmission Control Module
C2 (Diesel)BK Right Rear Side of Engine
Compartment8
Transmission Solenoid (4.0L
Gas)BK Left Side of Transmission 12
Transmission Solenoid
Assembly (Diesel)BK On Transmission 8
Transmission Solenoid/TRS
Assembly (4.7L)GY Left Side of Transmission 16
Underhood Lamp BK At Lamp 6
Vehicle Information Center BK In Overhead Console N/S
Viscous/Cabin Heater (Diesel) BK Left Rear of Engine Compartment N/S
Washer Fluid Level Switch GY Left Front of Engine Compartment 3, 4
Wastegate Solenoid (Diesel) Near Power Distribution Center N/S
Water In Fuel Sensor (Diesel) BK Left Rear of Engine Compartment N/S
GROUNDS
GROUND NUMBER LOCATION FIG.
G100 (4.0L and Diesel) Near Starter N/S
G100 (4.7L) Near Intake Plenum N/S
G101 Near Battery 2
G102 Right Side of Engine 14, 15
G103 Right Side of Engine 7, 8, 10, 11, 14, 15
G104 (4.0L) Right Rear of Engine 10, 11
G104 (4.7L) Left Side of Engine 13
G105 Right Side of Engine 8
G106 Left Side of Engine Compartment 3, 4
G107 Left Side of Engine Compartment 3, 4
G108 Near Power Distribution Center 5
G200 Near Airbag Control Module 19, 20, 21, 22
G201 Near Airbag Control Module 19, 20, 21, 22
G300 Near Right Front Seat 34, 36
G301 Near Left Front Seat 33, 35
WJ8W-91 CONNECTOR/GROUND/SPLICE LOCATION 8W - 91 - 11
CONNECTOR/GROUND/SPLICE LOCATION (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
SLIPS IN OVERDRIVE
FOURTH GEAR1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Overdrive Clutch Pack Worn. 2. Remove overdrive unit and rebuild clutch pack.
3. Overdrive Piston Retainer Bleed
Orifice Blown Out.3. Disassemble transmission, remove retainer and
replace orifice.
4. Overdrive Piston or Seal
Malfunction.4. Remove overdrive unit. Replace seals if worn.
Replace piston if damaged. If piston retainer is
damaged, remove and disassemble the
transmission.
5. 3-4 Shift Valve, Timing Valve or
Accumulator Malfunction.5. Remove and overhaul valve body. Replace
accumulator seals. Make sure all valves operate
freely in bores and do not bind or stick. Make sure
valve body screws are correctly tightened and
separator plates are properly positioned.
6. Overdrive Unit Thrust Bearing
Failure.6. Disassemble overdrive unit and replace thrust
bearing (NO. 1 thrust bearing is between
overdrive piston and clutch hub; NO. 2 thrust
bearing is between the planetary gear and the
direct clutch spring plate; NO. 3 thrust bearing is
between overrunning clutch hub and output shaft).
7. O/D Check Valve/Bleed Orifice
Failure.7. Check for function/secure orifice insert in O/D
piston retainer.
DELAYED 3-4
UPSHIFT (SLOW TO
ENGAGE)1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Throttle Valve Cable Mis-
adjusted.2. Adjust throttle valve cable.
3. Overdrive Clutch Pack
Worn/Burnt.3. Remove unit and rebuild clutch pack.
4. TPS Faulty. 4. Test with DRBTscan tool and replace as
necessary
5. Overdrive Clutch Bleed Orifice
Plugged.5. Disassemble transmission and replace orifice.
6. Overdrive Solenoid or Wiring
Shorted/Open.6. Test solenoid and check wiring for loose/
corroded connections or shorts/grounds. Replace
solenoid if faulty and repair wiring if necessary.
7. Overdrive Excess Clearance. 7. Remove unit. Measure end play and select
proper spacer.
8. O/D Check Valve Missing or
Stuck.8. Check for presence of check valve. Repair or
replace as required.
TORQUE
CONVERTER LOCKS
UP IN SECOND
AND/OR THIRD
GEARLockup Solenoid, Relay or Wiring
Shorted/Open.Test solenoid, relay and wiring for continuity,
shorts or grounds. Replace solenoid and relay if
faulty. Repair wiring and connectors as necessary.
HARSH 1-2, 2-3, 3-4
OR 3-2 SHIFTSLockup Solenoid Malfunction. Remove valve body and replace solenoid
assembly.
21 - 24 AUTOMATIC TRANSMISSION - 42REWJ
AUTOMATIC TRANSMISSION - 42RE (Continued)

Normal calibration will be performed when sump
temperature is above 50 degrees F, or in the absence
of sump temperature data, after the first 10 minutes
of vehicle operation. Calibration of the pressure
transducer offset occurs each time the output shaft
speed falls below 200 RPM. Calibration shall be
repeated each 3 seconds the output shaft speed is
below 200 RPM. A 0.5 second pulse of 95% duty cycle
is applied to the governor pressure solenoid valve
and the transducer output is read during this pulse.
Averaging of the transducer signal is necessary to
reject electrical noise.
Under cold conditions (below 50 degrees F sump),
the governor pressure solenoid valve response may
be too slow to guarantee 0 psi during the 0.5 second
calibration pulse. Calibration pulses are continued
during this period, however the transducer output
valves are discarded. Transducer offset must be read
at key-on, under conditions which promote a stable
reading. This value is retained and becomes the off-
set during the9cold9period of operation.
GOVERNOR PRESSURE SOLENOID VALVE
The inlet side of the solenoid valve is exposed to
normal transmission line pressure. The outlet side of
the valve leads to the valve body governor circuit.
The solenoid valve regulates line pressure to pro-
duce governor pressure. The average current sup-
plied to the solenoid controls governor pressure. One
amp current produces zero kPa/psi governor pres-
sure. Zero amps sets the maximum governor pres-
sure.
The powertrain control module (PCM) turns on the
trans control relay which supplies electrical power to
the solenoid valve. Operating voltage is 12 volts
(DC). The PCM controls the ground side of the sole-
noid using the governor pressure solenoid control cir-
cuit.
GOVERNOR PRESSURE SENSOR
The sensor output signal provides the necessary
feedback to the PCM. This feedback is needed to ade-
quately control governor pressure.
GOVERNOR BODY AND TRANSFER PLATE
The transfer plate channels line pressure to the
solenoid valve through the governor body. It also
channels governor pressure from the solenoid valve
to the governor circuit. It is the solenoid valve that
develops the necessary governor pressure.
GOVERNOR PRESSURE CURVES
LOW TRANSMISSION FLUID TEMPERATURE
When the transmission fluid is cold the conven-
tional governor can delay shifts, resulting in higherthan normal shift speeds and harsh shifts. The elec-
tronically controlled low temperature governor pres-
sure curve is higher than normal to make the
transmission shift at normal speeds and sooner. The
PCM uses a temperature sensor in the transmission
oil sump to determine when low temperature gover-
nor pressure is needed.
NORMAL OPERATION
Normal operation is refined through the increased
computing power of the PCM and through access to
data on engine operating conditions provided by the
PCM that were not available with the previous
stand-alone electronic module. This facilitated the
development of a load adaptive shift strategy - the
ability to alter the shift schedule in response to vehi-
cle load condition. One manifestation of this capabil-
ity is grade9hunting9prevention - the ability of the
transmission logic to delay an upshift on a grade if
the engine does not have sufficient power to main-
tain speed in the higher gear. The 3-2 downshift and
the potential for hunting between gears occurs with a
heavily loaded vehicle or on steep grades. When
hunting occurs, it is very objectionable because shifts
are frequent and accompanied by large changes in
noise and acceleration.
WIDE OPEN THROTTLE OPERATION
In wide-open throttle (WOT) mode, adaptive mem-
ory in the PCM assures that up-shifts occur at the
preprogrammed optimum speed. WOT operation is
determined from the throttle position sensor, which
is also a part of the emission control system. The ini-
tial setting for the WOT upshift is below the opti-
mum engine speed. As WOT shifts are repeated, the
PCM learns the time required to complete the shifts
by comparing the engine speed when the shifts occur
to the optimum speed. After each shift, the PCM
adjusts the shift point until the optimum speed is
reached. The PCM also considers vehicle loading,
grade and engine performance changes due to high
altitude in determining when to make WOT shifts. It
does this by measuring vehicle and engine accelera-
tion and then factoring in the shift time.
TRANSFER CASE LOW RANGE OPERATION
On four-wheel drive vehicles operating in low
range, the engine can accelerate to its peak more
rapidly than in Normal range, resulting in delayed
shifts and undesirable engine9flare.9The low range
governor pressure curve is also higher than normal
to initiate upshifts sooner. The PCM compares elec-
tronic vehicle speed signal used by the speedometer
to the transmission output shaft speed signal to
determine when the transfer case is in low range.
21 - 66 AUTOMATIC TRANSMISSION - 42REWJ
ELECTRONIC GOVERNOR (Continued)

1-2 SHIFT CONTROL VALVE
It contains a valve with four lands and a spring. It
is used as both a ªrelayº and ªbalancedº valve.
The valve has two specific operations (Fig. 268):
²Aid in quality of the 1-2 upshift.
²Aid in the quality and timing of the 3-2 kick-
down ranges.
When the manual valve is set to the DRIVE posi-
tion and the transmission is in the first or second
gear range, 1-2 shift control or ªmodulated throttle
pressureº is supplied to the middle of the accumula-
tor piston by the 1-2 shift control valve. During the1-2 upshift, this pressure is used to control the kick-
down servo apply pressure that is needed to apply
the kickdown and accumulator pistons. Thus, the 1-2
shift point is ªcushionedº and the quality is
improved. During a WOT kickdown, kickdown pres-
sure is applied between the kickdown valve and the
1-2 shift control valve. This additional pressure is
directed to the 1-2 shift control's spring cavity, add-
ing to the spring load on the valve. The result of this
increased ªmodulatedº throttle pressure is a firmer
WOT upshift.
Fig. 268 1-2 Shift Control Valve
21 - 146 AUTOMATIC TRANSMISSION - 42REWJ
VALVE BODY (Continued)