2002 JEEP GRAND CHEROKEE Neutral

BRAKE TRANSMISSION SHIFT
INTERLOCK MECHANISM
DESCRIPTION
The Brake Transmission Shifter/Ignition Interlock
(BTSI), is a cable and solenoid operated system. It
interconnects the automatic transmission floor
mounted shifter to the steering column ignition
switch (Fig. 57).
OPERATION
The system locks the shifter into the PARK posi-
tion. The interlock system is engaged whenever the
ignition switch is in the LOCK or ACCESSORY posi-
tion. An additional electrically activated feature will
prevent shifting out of the PARK position unless the
brake pedal is depressed approximately one-half an
inch. A magnetic holding device in the shifter assem-
bly is energized when the ignition is in the RUN
position. When the key is in the RUN position and
the brake pedal is depressed, the shifter is unlocked
and will move into any position. The interlock system
also prevents the ignition switch from being turned
to the LOCK or ACCESSORY position, unless the
shifter is fully locked into the PARK position.
DIAGNOSIS AND TESTING - BRAKE
TRANSMISSION SHIFT INTERLOCK
(1) Verify that the key can only be removed in the
PARK position
(2) When the shift lever is in PARK And the shift
handle pushbutton is in the ªOUTº position, the igni-
tion key cylinder should rotate freely from OFF to
LOCK. When the shifter is in any other gear or neu-
tral position, the ignition key cylinder should not
rotate to the LOCK position.
(3) Shifting out of PARK should not be possible
when the ignition key cylinder is in the OFF posi-
tion.
(4) Shifting out of PARK should not be possible
while applying normal pushbutton force and ignition
key cylinder is in the RUN or START positions
unless the foot brake pedal is depressed approxi-
mately 1/2 inch (12mm).
(5) Shifting out of PARK should not be possible
when the ignition key cylinder is in the ACCESSORY
or LOCK positions.
(6) Shifting between any gears, NEUTRAL or into
PARK may be done without depressing foot brake
pedal with ignition switch in RUN or START posi-
tions.
Fig. 57 Ignition Interlock Cable
1 - SHIFT MECHANISM 4 - STEERING COLUMN ASSEMBLY
2 - SHIFTER BTSI LEVER 5 - INTERLOCK CABLE
3 - ADJUSTMENT CLIP
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ADJUSTMENTS - BRAKE TRANSMISSION
SHIFT INTERLOCK
The park interlock cable is part of the brake/shift
lever interlock system. Correct cable adjustment is
important to proper interlock operation. The gear
shift and park lock cables must both be correctly
adjusted in order to shift out of PARK.
ADJUSTMENT PROCEDURE
(1) Remove floor console as necessary for access to
the brake transmission shift interlock cable. (Refer to
23 - BODY/INTERIOR/FLOOR CONSOLE -
REMOVAL)
(2) Shift the transmission into the PARK position.
(3) Turn ignition switch to LOCK position.Be
sure ignition key cylinder is in the LOCK posi-
tion. Cable will not adjust correctly in any
other position.
(4) Pull cable lock button up to release cable (Fig.
58).
(5) Ensure that the cable is free to self-adjust by
pushing cable rearward and releasing.
(6) Push lock button down until it snaps in place.
BTSI FUNCTION CHECK
(1) Verify removal of ignition key allowed in PARK
position only.
(2) When the shift lever is in PARK, and the shift
handle push-button is in the out position, the igni-
tion key cylinder should rotate freely from off to lock.
When the shifter is in any other position, the ignition
key should not rotate from off to lock.
(3) Shifting out of PARK should be possible when
the ignition key cylinder is in the off position.
(4) Shifting out of PARK should not be possible
while applying normal push-button force, and igni-
tion key cylinder is in the run or start positions,
unless the foot brake pedal is depressed approxi-
mately 1/2 inch (12mm).
(5) Shifting out of PARK should not be possible
when the ignition key cylinder is in the accessory or
lock position.
(6) Shifting between any gear and NEUTRAL, or
PARK, may be done without depressing foot brake
with ignition switch in run or start positions.
(7) The floor shifter lever and gate positions
should be in alignment with all transmission detent
positions.
Fig. 58 Brake Transmission Shift Interlock Cable
1 - SHIFT MECHANISM 4 - STEERING COLUMN ASSEMBLY
2 - SHIFTER BTSI LEVER 5 - INTERLOCK CABLE
3 - ADJUSTMENT CLIP
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BRAKE TRANSMISSION SHIFT INTERLOCK MECHANISM (Continued)

(8) Engine starts must be possible with shifter
lever in PARK or NEUTRAL gate positions only.
Engine starts must not be possible in any other gate
positions other than PARK or NEUTRAL.
(9) With shifter lever handle push-button not
depressed and lever detent in:
²PARK position- apply forward force on center of
handle and remove pressure. Engine start must be
possible.
²PARK position- apply rearward force on center
of handle and remove pressure. Engine start must be
possible.
²NEUTRAL position- engine start must be possi-
ble.
²NEUTRAL position, engine running and brakes
applied- Apply forward force on center of shift han-
dle. Transmission should not be able to shift into
REVERSE detent.
FLUID AND FILTER
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air
along with the fluid. Air in the fluid will cause fluid
pressures to be low and develop slower than normal.
If the transmission is overfilled, the gears churn the
fluid into foam. This aerates the fluid and causing
the same conditions occurring with a low level. In
either case, air bubbles cause fluid overheating, oxi-
dation and varnish buildup which interferes with
valve and clutch operation. Foaming also causes fluid
expansion which can result in fluid overflow from the
transmission vent or fill tube. Fluid overflow can eas-
ily be mistaken for a leak if inspection is not careful.
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID
Burnt, discolored fluid is a result of overheating
which has three primary causes.
(1) Internal clutch slippage, usually caused by low
line pressure, inadequate clutch apply pressure, or
clutch seal failure.
(2) A result of restricted fluid flow through the
main and/or auxiliary cooler. This condition is usu-
ally the result of a faulty or improperly installed
drainback valve, a damaged main cooler, or severe
restrictions in the coolers and lines caused by debris
or kinked lines.(3) Heavy duty operation with a vehicle not prop-
erly equipped for this type of operation. Trailer tow-
ing or similar high load operation will overheat the
transmission fluid if the vehicle is improperly
equipped. Such vehicles should have an auxiliary
transmission fluid cooler, a heavy duty cooling sys-
tem, and the engine/axle ratio combination needed to
handle heavy loads.
DIAGNOSIS AND TESTING - FLUID
CONTAMINATION
Transmission fluid contamination is generally a
result of:
²adding incorrect fluid
²failure to clean dipstick and fill tube when
checking level
²engine coolant entering the fluid
²internal failure that generates debris
²overheat that generates sludge (fluid break-
down)
²failure to reverse flush cooler and lines after
repair
²failure to replace contaminated converter after
repair
The use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failure
due to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped
clean before checking fluid level. Dirt, grease and
other foreign material on the cap and tube could fall
into the tube if not removed beforehand. Take the
time to wipe the cap and tube clean before withdraw-
ing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The transmission cooler and lines should be
reverse flushed whenever a malfunction generates
sludge and/or debris. The torque converter should
also be replaced at the same time.
Failure to flush the cooler and lines will result in
recontamination. Flushing applies to auxiliary cool-
ers as well. The torque converter should also be
replaced whenever a failure generates sludge and
debris. This is necessary because normal converter
flushing procedures will not remove all contami-
nants.
21 - 228 AUTOMATIC TRANSMISSION - 545RFEWJ
BRAKE TRANSMISSION SHIFT INTERLOCK MECHANISM (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transmssion has too much fluid, the
geartrain churns up foam and cause the same condi-
tions which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can inter-
fere with normal valve, clutch, and accumulator opera-
tion. Foaming can also result in fluid escaping from the
transmission vent where it may be mistaken for a leak.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
The transmission has a dipstick to check oil level.
It is located on the right side of the engine. Be sure
to wipe all dirt from dipstick handle before removing.
The torque converter fills in both the P (PARK)
and N (NEUTRAL) positions. Place the selector lever
in P (PARK) to be sure that the fluid level check is
accurate.The engine should be running at idle
speed for at least one minute, with the vehicle
on level ground.At normal operating temperature(approximately 82 C. or 180 F.), the fluid level is cor-
rect if it is in the HOT region (cross-hatched area) on
the oil level indicator. The fluid level will be approx-
imately at the upper COLD hole of the dipstick at
70É F fluid temperature.
NOTE: Engine and Transmission should be at nor-
mal operating temperature before performing this
procedure.
(1) Start engine and apply parking brake.
(2) Shift the transmission into DRIVE for approxi-
mately 2 seconds.
(3) Shift the transmission into REVERSE for
approximately 2 seconds.
(4) Shift the transmission into PARK.
(5)
Hook up DRBtscan tool and select transmission.
(6) Select sensors.
(7) Read the transmission temperature value.
(8) Compare the fluid temperature value with the
chart. (Fig. 59)
(9) Adjust transmission fluid level shown on the
dipstick according to the chart.
NOTE: After adding any fluid to the transmission,
wait a minimum of 2 minutes for the oil to fully
drain from the fill tube into the transmission before
rechecking the fluid level.
(10) Check transmission for leaks.
Fig. 59 Transmission Fluid Temperature Chart
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 229
FLUID AND FILTER (Continued)

GEARSHIFT CABLE
DIAGNOSIS AND TESTING - GEARSHIFT
CABLE
(1) The floor shifter lever and gate positions
should be in alignment with all transmission PARK,
NEUTRAL, and gear detent positions.
(2) Engine starts must be possible with floor shift
lever in PARK or NEUTRAL gate positions only.
Engine starts must not be possible in any other gear
position.
(3) With floor shift lever handle push-button not
depressed and lever in:
(a) PARK position - Apply forward force on cen-
ter of handle and remove pressure. Engine starts
must be possible.
(b) PARK position - Apply rearward force on cen-
ter of handle and remove pressure. Engine starts
must be possible.
(c) NEUTRAL position - Normal position. Engine
starts must be possible.
(d) NEUTRAL position - Engine running and
brakes applied, apply forward force on center of
shift handle. Transmission shall not be able to shift
from NEUTRAL to REVERSE.
REMOVAL
(1) Shift transmission into PARK.
(2) Raise vehicle.
(3) Remove the shift cable eyelet from the trans-
mission manual shift lever (Fig. 61).
(4) Remove shift cable from the cable support
bracket.
(5) Lower vehicle.(6) Remove necessary console parts for access to
shift lever assembly and shift cable. (Refer to 23 -
BODY/INTERIOR/FLOOR CONSOLE - REMOVAL)
(7) Disconnect cable at shift lever and shifter
assembly bracket (Fig. 62).
(8) Remove the nuts holding the shift cable seal
plate to the floor pan (Fig. 63).
(9) Pull cable through floor panel opening.
(10) Remove shift cable from vehicle.
INSTALLATION
(1) Route cable through hole in floor pan.
(2) Install seal plate to studs in floor pan.
Fig. 61 Remove Shift Cable From Transmission
1 - SHIFT CABLE
2 - MANUAL LEVER
3 - MANUAL LEVER
Fig. 62 Transmission Shift Cable at Shifter
1 - SHIFT LEVER PIN
2 - ADJUSTMENT SCREW
3 - SHIFT CABLE
4 - SHIFTER ASSEMBLY BRACKET
Fig. 63 Shift Cables at Floor Pan
1 - SEAL PLATES
2 - TRANSMISSION SHIFT CABLE
3 - TRANSFER CASE SHIFT CABLE
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 231

(3) Install nuts to hold seal plate to floor pan.
Tighten nuts to 7 N´m (65 in.lbs.).
(4) Install the shift cable to the shifter assembly
bracket. Push cable into the bracket until secure.
(5) Place the floor shifter lever in PARK position.
(6) Loosen the adjustment screw on the shift cable.
(7) Snap the shift cable onto the shift lever pin.
(8) Raise the vehicle.
(9) Install the shift cable to the shift cable support
bracket.
(10) Shift the transmission into PARK. PARK is
the rearmost detent position on the transmission
manual shift lever.
(11) Snap the shift cable onto the transmission
manual shift lever.
(12) Lower vehicle.
(13) Verify that the shift lever is in the PARK posi-
tion.
(14) Tighten the adjustment screw to 7 N´m (65
in.lbs.).
(15) Verify correct shifter operation.
(16) Install any console parts removed for access to
shift lever assembly and shift cable. (Refer to 23 -
BODY/INTERIOR/FLOOR CONSOLE - INSTALLA-
TION)
ADJUSTMENTS - GEARSHIFT CABLE
Check adjustment by starting the engine in PARK
and NEUTRAL. Adjustment is CORRECT if the
engine starts only in these positions. Adjustment is
INCORRECT if the engine starts in one but not both
positions. If the engine starts in any position other
than PARK or NEUTRAL, or if the engine will not
start at all, the park/neutral position switch or TRS
may be faulty.
(1) Shift transmission into PARK.
(2) Remove floor console as necessary for access to
the shift cable adjustment. (Refer to 23 - BODY/IN-
TERIOR/FLOOR CONSOLE - REMOVAL)
(3) Loosen the shift cable adjustment screw (Fig.
64).
(4) Raise vehicle.
(5) Unsnap cable eyelet from transmission shift
lever (Fig. 65).
(6) Verify transmission shift lever is in PARK
detent by moving lever fully rearward. Last rearward
detent is PARK position.
(7) Verify positive engagement of transmission
park lock by attempting to rotate propeller shaft.
Shaft will not rotate when park lock is engaged.
(8) Snap cable eyelet onto transmission shift lever.
(9) Lower vehicle
(10) Tighten the shift cable adjustment screw to 7
N´m (65 in.lbs.).
(11) Verify correct operation.(12) Install any floor console components removed
for access. (Refer to 23 - BODY/INTERIOR/FLOOR
CONSOLE - INSTALLATION)
Fig. 64 Shift Cable at the Shifter
1 - SHIFT LEVER PIN
2 - ADJUSTMENT SCREW
3 - SHIFT CABLE
4 - SHIFTER ASSEMBLY BRACKET
Fig. 65 Shift Cable at Transmission
1 - TRANSMISSION SHIFTER CABLE
2 - THROTTLE VALVE CABLE
3 - TRANSFER CASE SHIFTER CABLE
4 - TRANSFER CASE SHIFTER CABLE BRACKET RETAINING
BOLT(S)
5 - THROTTLE VALVE CABLE BRACKET RETAINING BOLT
6 - ELECTRICAL CONNECTORS
7 - TRANSMISSION FLUID LINES
21 - 232 AUTOMATIC TRANSMISSION - 545RFEWJ
GEARSHIFT CABLE (Continued)

OPERATION
2C CLUTCH
The 2C clutch is hydraulically applied in second
and fifth gear by pressurized fluid against the 2C
piston. When the 2C clutch is applied, the reverse
sun gear assembly is held or grounded to the trans-
mission case by holding the reaction planetary car-
rier.
4C CLUTCH
The 4C clutch is hydraulically applied in second
prime and fourth gear by pressurized fluid againstthe 4C clutch piston. When the 4C clutch is applied,
the reaction annulus gear is held or grounded to the
transmission case.
LOW/REVERSE CLUTCH
The Low/Reverse clutch is hydraulically applied in
park, reverse, neutral, and first gear, only at low
speeds, by pressurized fluid against the Low/Reverse
clutch piston. When the Low/Reverse clutch is
applied, the input annulus assembly is held or
grounded to the transmission case.
Fig. 67 Low/Reverse Clutch
1 - SNAP-RING (SELECT) 8 - SEAL
2 - REACTION PLATE 9 - BELLEVILLE SPRING
3 - DISC 10 - RETAINER
4 - PLATE 11 - SNAP-RING
5 - L/R CLUTCH RETAINER 12 - OVERRUNNING CLUTCH
6 - SEAL 13 - SNAP-RING
7 - PISTON
21 - 234 AUTOMATIC TRANSMISSION - 545RFEWJ
HOLDING CLUTCHES (Continued)

(3) Install the wiring connector onto the input
speed sensor
(4) Verify the transmission fluid level. Add fluid as
necessary.
(5) Lower vehicle.
LINE PRESSURE (LP) SENSOR
DESCRIPTION
The TCM utilizes a closed-loop system to control
transmission line pressure. The system contains a
variable force style solenoid, the Pressure Control
Solenoid, mounted on the side of the solenoid and
pressure switch assembly. The solenoid is duty cycle
controlled by the TCM to vent the unnecessary line
pressure supplied by the oil pump back to the sump.
The system also contains a variable pressure style
sensor, the Line Pressure Sensor, which is a direct
input to the TCM. The line pressure solenoid moni-
tors the transmission line pressure and completes the
feedback loop to the TCM. The TCM uses this infor-
mation to adjust its control of the pressure control
solenoid to achieve the desired line pressure.
OPERATION
The TCM calculates the desired line pressure
based upon inputs from the transmission and engine.
The TCM calculates the torque input to the trans-
mission and uses that information as the primary
input to the calculation. The line pressure is set to a
predetermined value during shifts and when the
transmission is in the PARK and NEUTRAL posi-tions. This is done to ensure consistent shift quality.
During all other operation, the actual line pressure is
compared to the desired line pressure and adjust-
ments are made to the pressure control solenoid duty
cycle.
REMOVAL
(1) Raise vehicle.
(2) Place a suitable fluid catch pan under the
transmission.
(3) Remove the wiring connector from the line
pressure sensor (Fig. 83).
(4) Remove the bolt holding the line pressure sen-
sor to the transmission case.
(5) Remove the line pressure sensor from the
transmission case.
INSTALLATION
(1) Install the line pressure sensor into the trans-
mission case.
(2) Install the bolt to hold the line pressure sensor
into the transmission case. Tighten the bolt to 11.9
N´m (105 in.lbs.).
(3) Install the wiring connector onto the line pres-
sure sensor
(4) Verify the transmission fluid level. Add fluid as
necessary.
(5) Lower vehicle.
Fig. 82 Input Speed Sensor
1 - OUTPUT SPEED SENSOR
2 - LINE PRESSURE SENSOR
3 - INPUT SPEED SENSOR
Fig. 83 Line Pressure Sensor
1 - OUTPUT SPEED SENSOR
2 - LINE PRESSURE SENSOR
3 - INPUT SPEED SENSOR
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 245
INPUT SPEED SENSOR (Continued)