oil temperature ISUZU TROOPER 1995 Owner's Guide
[x] Cancel search | Manufacturer: ISUZU, Model Year: 1995, Model line: TROOPER, Model: ISUZU TROOPER 1995Pages: 1928
Page 834 of 1928

6E2-138 DRIVEABILITY AND EMISSIONS
SECTION C4
ELECTRONIC IGNITION (EI) SYSTEM/IGNITION CONTROL (IC)
CONTENTS
General Description . . . . . . . . . . . . . . . . . . . . . 6E2-138
Purpose
............................ 6E2-138
Operation
........................... 6E2-138
Results of Incorrect Operation . . . . . . . . . . . 6E2-139
How diagnostic trouble code (DTC) 42 is
Determined ........................ 6E2-139
Diagnosis. . . . . . . . . . . . . . . ............. 6E2-139
Diagnostic
trouble code (DTC) 12 . . . . . . . . . 6E2-139
On-Vechicle Service . .
. . . . . . . . . . . . . . . . . . . 6E2-139
Electronic Ignition (EI) Assembly .......... 6E2-139
Crankshaft Position (CKP) Sensor ......... 6E2-140
Ignition Coil
.......................... 6E2-140
Ignition Control
Module (ICM) ............ 6E2-140
Ignition
Timing ....................... 6E2-140
Chart
C-4D-1 Electronic Ignition (EI) misfire
at
Idle .............................. 6E2-142
Chart C-4D-2 Electronic Ignition (EI) misfire
Under Load .......................... 6E2-144
GENERAL DESCRIPTION
PURPOSE
The Electronic Ignition (EI) system controls fuel
combustion by providing a spark to ignite the
compressed
air/fuel mixture at the correct time. To
provide improved engine performance,
fuel economy,
and
control of exhaust emissions, the Engine Control
Module
(ECM) controls spark advance timing with the
Ignition Control (IC) system.
OPERATION
The "EI" is a "waste spark" system in which 2 plugs are
fired
simultaneously from one coil. The spark plugs are
paired
to a coil, so that when both fire, one cylinder is
on the compression stroke and the other is on exhaust.
There is
Iitie resistance across the plug gap on the
exhaust stroke, so the
plug requires very little voltage
to fire, thereby providing the other plug (compression)
with maximum available voltage.
The system uses a magnetic Crankshaft Position (CKP)
sensor which protrudes into the block, within
approximately .050" of the crankshaft reluctor. The
reluctor is a special wheel cast on the crankshaft that
has seven machined
slots, six of which are equally
spaced 60° apart). The seventh slot is spaced 1 oo from
one
of the other slots. As the reluctor rotates with the
crankshaft, the
slots change the magnetic field of the
sensor, causing
an induced voltage pulse.
By counting the time between pulses, the Ignition
Control Module (ICM)
can recognize the pulse of the
seventh
slot (sync pulse). Based on this sync pulse, the
module sends the reference signal to the ECM to
calculate CKP (used to fire coils in correct sequence)
and engine speed.
To
properly control timing, the ECM relies on the
following information:
• Engine load (manifold absolute pressure or
vacuum).
• Atmospheric (barometric) pressure.
• Engine temperature.
• Intake air temperature.
• CKP
• Engine speed (revolution per minute).
The ignition
control system consisits of the "EI"
assembly (coils, module,
and CKP sensor), ECM and
connecting wires. These circuits
perform the following
functions:
• "EI" reference
The CKP sensor sends a signal to the ICM which
generates a reference
pulse which is sent to the
ECM. The ECM uses this signal to calculate CKP
and engine speed (also used to trigger the
injector).
• Reference ground (GND)
This wire is GNd through the module and makes
sure the GNd circuit has no
voltage drop between
the
ICM and the ECM, which if open, could affect
performance.
• Bypass
At about 400 revolution per minute, the ECM
applies 5 volts to this circuit to switch spark timing
control from the ICM to the ECM. An open or
grounded bypass circuit
will set a diagnostic
trouble code 42 and the engine will run at base
timing,
plus a small amount of advance built into
the
ICM.
• IGNITION CONTROL (IC)
The ECM uses this circuit (when bypass voltage is
applied) to trigger the "EI" module. The ECM uses
the
CKP to base its calculation of the amount of
spark advance needed under present engine
conditions.
•
Page 835 of 1928

RESULTS OF INCORRECT OPERATION
An open or ground in the Ignition Control (I C) or bypass
circuits
will set a Diagnostic Trouble Code (DTC) 42 and
cause the engine
to run on the Ignition Control Module
(ICM)
timing.
The Engine
Control Module (ECM) uses information
from the Intake Air Temperature (IAT) and engine
coolant sensors in addition to revolution per minute
(rpm) to
calculate spark advance as follows:
• Cold
engine -more spark advance.
• Engine under minimum load based on rpm and
low amount of air flow = more spark advance.
• Hot engine = less spark advance.
• Engine under heavy load based on rpm and high
air
flow = less spark advance.
HOW DIAGNOSTIC TROUBLE CODE (DTC)
42 IS DETERMINED
When the system is running on the ICM, that is, no
voltage on the bypass line, the ICM grounds (GND) the
IC signal. The ECM expects to see no voltage on the IC
line during this condition.lf it sees a voltage, it sets DTC
42 and will not go into the IC mode.
DRIVEABILITY AND EMISSIONS 6E2-139
When the rpm for IC is reached (about 400 rpm) the
ECM applies 5 volts to the bypass line and the IC should
no longer be grounded in the ICM so the IC voltage
should
be varying.
An open in the
IC circuit while running, will result in the
engine continuing to run, but in a back-up
ig~it~on
timing mode (module timing) at a calculated t1mmg
value
and the malfunction indicator lamp will not be
"ON".
If
the IC circuit is shorted to GND, the "Check Engine"
malfunction
indicator lamp will be turned "ON", and a
DTC 42 will be set and the engine will operate in
module timing. Either condition may cause poor
performance and reduced
fuel economy.
If the bypass line is open or GND, the ICM will not
switch to IC mode so the IC voltage will be low and DTC
42 will be set.
If the IC line is grounded, the ICM will switch to IC, but
because the line isGNDtherewill be no ICsignai.A DTC
42 will be set.
DIAGNOSIS
If the engine cranks but will not run, CHART A-3 will be
used to determine if the Electronic Ignition (EI) system
is the cause
of the problem or if it is another part of the
fuel injection system.
If DTC 42 is set, that DTC chart should be used for
diagnosis. If no DTC is set and the ignition system is
suspected, use
CHART C4-D ("EI" Misfire) for
diagnosis.
DIAGNOSTIC TROUBLE CODE (DTC) 12
DTC 12 is used during the on-board diagnostic system
check procedure to test the
DTC display ability of the
ECM. This diagnostic trouble code indicates that the
ECM is not receiving the engine speed (REFERENCE)
signal. This occurs with the ignition key "ON" and the
engine not running.
The "reference"
signal also triggers the fuel injection
system.
Without the "reference" signal the engine
cannot run.
ON-VEHICLE SERVICE
ELECTRONIC IGNITION (EI) ASSEMBLY
1••1 REMOVE OR DISCONNECT
1. Negative battery cable
2. "EI" electrical connectors (3)
3. Spark plug wires. (Note wire positions to proper
coils) (6)
4. "EI" assembly to bracket bolts (3)
5. "EI" assembly from Intake Plenum.
1••1 INSTALL OR CONNECT
1. "EI" assembly bracket to Intake Plenum
Tighten bolts to 25 N·m (19 lb·ft)
2. Spark plug wires to correct spark plugs
3. "EI" electrical connectors
4. Negative battery cable
Page 839 of 1928

DRIVEABILITV AND EMISSIONS 6E2-143
CHART C-40
ELECTRONIC IGNITION (EI) MISFIRE AT IDLE
CD • IF ENGINE MISFIRES UNDER LOAD ONLY, SEE CHART C-4D-2. • ENGINE IDLING AT NORMAL OPERATING TEMPERATURE, DISCONNECT IDLE AIR CONTROL. • MOMENTARILY DISCONNECT EACH SPARK PLUG LEAD, USING INSULATED PLIERS,
WHILE OBSERVING ENGINE SPEED. SEE CAUTION*. • ALL PLUG LEAD(S) SHOULD RESULT IN A REVOLUTION PER MINUTE DROP. DID THEY?
$ $
•
WITH IGNITION "OFF", INSTALL SPARK TESTER (ST-125) J-26792 OR I SEE "ROUGH, UNSTABLE OR INCORRECT IDLE
EQUIVALENT ON PLUG LEAD(S) WHOSE REMOVAL DID NOT RESULT IN OR STALLING" IN SYMPTOMS Si€'FISN "B". REVOLUTION PER MINUTE DROP. • SPARK SHOULD JUMP TESTER GAP WHILE CRANKING ENGINE. DOES IT?
$ $
•
WITH IGNITION "OFF", GROUND THE OPPOSITE PLUG CHECK FOR: @
LEAD OF THE AFFECTED COIL AT SPARK PLUG. -
FAUL TV, WORN OR CRACKED SPARK PLUG(S). • SPARK SHOULD JUMP TESTER GAP WHILE CRANKING -PLUG FOULING DUE TO ENGINE MECHANICAL FAULT. ENGINE. DOES IT? IF SPARK PLUGS CHECK OUT OK, REFER TO "CUTS
OUT, MISSES" IN SYMPTOMS SiC'flet~ "B".
~ $
• CHECK THE RESISTANCE OF EACH PLUG WIRE OF THE REPLACE
THE SPARK PLUG FOR THE LEAD WHICH WAS COIL WHICH DID NOT FIRE THE SPARK TESTER. JUMPERED TO GROUND. IF MISFIRE
IS STILL PRESENT, • WIRE RESISTANCE SHOULD BE LESS THAN 30,000 START MISFIRE TEST AGAIN AT STEP 1. OHMS EACH AND WIRES SHOULD NOT BE GROUNDED.
ARE WIRES OK?
$ $
• REMOVE COIL RETAINING NUTS AND REMOVE COILS.
I
REPLACE FAUL TV WIRE(S).I
• COILS SHOULD BE FREE OF CARBON TRACKING. ARE THEY?
$ $
•
SWITCH A NORMALLY OPERATING COIL WITH THE REPLACE IGNITION
COIL. ALSO CHECK FOR COIL FROM PROBLEM CYLINDER. FAULTY PLUG WIRE CONNECTION(S) AND • SPARK SHOULD JUMP TESTER GAP AT PROBLEM WIRE NIPPLE(S) FOR CARBON TRACKING.
CYLINDER WHILE CRANKING ENGINE. DID IT?
$ $
ORIGINAL IGNITION
I
REPLACE ELECTRONIC IGNITION MODULE. COIL IS FAUL TV.
*CAUTION: When handling secondary spark plug leads with engine running, insulated pliers must be used and care exercised to
prevent a possible electrical shock.
CLEAR DIAGNOSTIC TROUBLE CODES AND CONFIRM "CLOSED LOOP" OPERATION AND NORMAL "CHECK ENGINE" MALFUNCTION
INDICATOR LAMP OPERATION.
Page 874 of 1928

7A-2 AUTOMATIC TRANSMISSION (4L30-E)
Valve Body Assembly (Adapter Case) ....... 7A-168 Third Clutch and Sprag Unit ....................... 7A-195
Transmission Control
Module (TCM) ......... 7A-169 Third Clutch .................................................. 7A-196
Speed Sensor (Extension Housing) ............ 7A-169 Sprag
Unit ....................................................
7A-198
Transmission
Oil Temperature Sensor Second
Clutch .............................................. 7A-199
(Adapter Case) ..........................................
7A-170 3-4 Accumulator Piston ............................... 7A-200
Front Oil Seal (Converter Housing) ............ 7A-170 Reverse Clutch Piston and Center
Rear
Oil Seal (Extension Housing) ............. 7A-171 Support ..................................................... 7 A-202
Unit Repair ........................................................ 7A-173 Overrun Clutch and Turbine Shaft ............. 7A-204
Transmission (4L30-E) ................................. 7A-173 Main Data and Specifications ......................... 7 A-207
Converter Housing and Oil Pump General
Specifications ................................. 7 A-207
Assembly .................................................. 7 A-189 Torque
Specifications .................................. 7A-208
Oil
Pump ....................................................... 7A-190 Special Tools .................................................... 7A-211
Main Case Valve Body ................................. 7A-191 4L30-E Parts List.. ............................................. 7A-213
Adapter Case Valve Body ............................ 7A-193 Hydraulic
Circuit Diagram .......... End of This Manual
GENERAL DESCRIPTION
The 4L30-E is a 4-speed fully-automatic transmission.
It uses a microcomputer as a control unit to judge
running conditions
including throttle opening rate
and vehicle speed, then
it sets the shifting point in
the
optimum timing so that best driving performance
can be achieved.
In addition, the built-in shift mode select function can
select three shift modes according to the driver's
preference.
• Normal mode-Normal shift pattern.
• Winter mode-Starts in 3rd gear to reduce
slippage on ice
or snow.
• Power mode has a delayed upshift for when
more powerful acceleration is required.
Also, the built-in fail-safe
function ("backup mode")
assures driving performance even if the vehicle
speed sensor,
throttle signal or any solenoid fails.
Further, the self-diagnostic
function conducts diag
nosis in a short time when the control system fails,
thus improving serviceability.
The major features of 4L30-E are as follows:
• A compact structure consisting of 2 sets of
planetary gears and flat torque converter.
• Electronic control selects the optimum shift
mode according
to the driving conditions.
• Electronic control maintains the optimum hy
draulic pressure for clutch, band brake as well as
transmission so that shift feeling is improved.
• Two sets of planetary gears reduce friction of
power train.
Also, a lock-up mechanism in the torque con
verter reduces fuel consumption.
• Wide gear ratio and high torque rate of torque
converter provide
excellent starting perform
ance.
MODEL YEAR 1994-95 CHANGES
The Transmission Control Module (TCM) for ISUZU
TROOPER
models equipped with 4L30-E is changed
from "BOSCH" to "DELCO ELECTRONICS"
manufacture.
The main differences
which will be encountered
while servicing concerned vehicles are as follows:
Diagnostic Trouble Codes (DTC):
DTC's are changed: For example, DTC for
transmission gear error will be as follows depending
on the TCM unit:
-
On the "DELCO" unit (1994-95) ......... DTC 61
-On the "BOSCH" unit (1993-prior) ..... DTC 41
TCM Pin Connector:
The pin connector is changed. Therefore the
connections
to be made for troubleshooting also
change.
Shift Alteration when TECH 1 Tool is connected
toTCM:
SHIFTS WILL BE HARSH WHEN TECH 1 IS
CONNECTED.
Connection of TECH 1 automatically forces maximum
line pressure during shifts only.
Normal line pressure checks at idle and stall spe
can be carried out.
/
/
I J I
/
l
•
Page 878 of 1928

7A-6 AUTOMATIC TRANSMISSION (4L30-E)
CONTROL SYSTEM DIAGRAM
L1J ~ (!) z L1J
I
I
lr
t:··
~ .. I I
I
I
AUTOMATIC TRANSMISSION ASSEMBLY
O.:a: :Eo LLJ(J) t-z --' L1J oVl
ENGINE COOLANT TEMPERATURE
ffio ~---a:O wz >LLJ z--' oo uCJ> w::C :::>u at-a:=> ~d
0 0 z ... w, --'"' o-.. (J)N t-.!-u.. J: CJ)
IGNITION
CONTROL .
MODULE
~==PO=W==ER==M=O=D=E=L=A=M=P~r.-------
r-------CHECK TRANS. LAMP
~=W=IN=T=E=R=M=O=D=E=LA=M=P~~--J---
::c u L1J a: 1-:.:: ::c <( :::> <( u L1J --' a: 1-(!) u al :::> >-L1J L1J 0 --' 1-~ z u a: :5 <( ~ ~ --' al Cl.
Cl. L1J i=
i= L1J ~ z :.:: --' --' <( L1J :5 :::> :::> a: z Cl. ::!: ::!: al 0
0 a: L1J 0 >-0 > --'o --' z (l._ 1-<( L1J Cl.Q 0 > __,...,
SHIFT
CONTROL
BAND APPLY CONTROL
TORQUE CONVERTER CLUTCH CONTROL
LINE PRESSURE CONTROL
SAFETY MODE
ON-BOARD DIAGNOSTIC
SYSTEM
TORQUE MANAGEMENT
ATF WARNING CONTROL
r-ABS CONTROL
L--A-T_F_w_A_R_N_I_N_G_L_A_M_P_...Jr---_l 1---------------'
0 L1J "'a: Bio wVl __,z uw J:Vl L1J >
POWER c): TRANSMIT
.... : OIL PRESSURE
CONTROL
MECHANICAL
...• : SIGNAL
LLJJ: ou ELECTRONIC ot:: -•: ::!:~ SIGNAL
KICK DOWN SWITCH
BRAKE SWITCH
POWER MODE SWITCH
WINTER MODE SWITCH
AIR CONDITIONING
SWITCH
ABS
SIGNAL (ASS CONTROLLER)
ABS: Anti-Lock Brake System
Fig. 7A-4
..
Page 879 of 1928

1. SHIFT CONTROL
The transmission gear is shifted according to the
shift pattern selected by the driver.
~ In shifting gears, the gear ratio is controlled by the
ON/ OFF signal using the 1-2/3-4 shift solenoids and
the 2-3 shift solenoid.
2. BAND APPLY CONTROL
The band apply is controlled when in the 3-2
downshift (engine overrun prevention) and the
garage shift (shock control).
The band
apply solenoid is controlled by the signal
from the Pulse Width Modulation (PWM) to regulate
the
flow of the oil.
3. TORQUE CONVERTER CLUTCH CONTROL
The clutch ON/OFF is controlled by moving the
converter clutch valve through shifting Torque
Converter Clutch
(TCC) solenoid using the ON/OFF
signal.
4. LINE PRESSURE CONTROL
The throttle signal allows the current signal to be
sent
to the force motor. After receiving the current
signal, the force motor activates the pressure
regulator valve to regulate the line pressure.
5. ON-BOARD DIAGNOSTIC SYSTEM
Several malfunction displays can be stored in the
Transmission Control Module (TCM) memory, and
read
out of it afterward.
The serial data lines, which are required for the
testing of the final assembly and the coupling to
other electronic modules, can be regulated by this
function.
6 FAIL-SAFE MECHANISM
If there is a problem in the transmission system, the
TCM will go into a "backup" mode. The vehicle can
still be driven, but the driver must use the gear
lever to shift gears.
7. TORQUE MANAGEMENT CONTROL
The TCM sends the absolute spark advance signal
to the Engine Control Module (ECM) while the
transmission is being shifted, to control the engine
spark timing in compliance with the vehicle running
condition to reduce the shocks caused by the
change of speed.
8. ATF WARNING CONTROL
The oil temperature sensor detects the ATF oil
temperature to control the oil temperature warning,
TCC and the winter mode.
9. ABS CONTROL
When the select lever is at "L" or "R" range, a
signal is sent
to the ABS controller as one of the
ABS control conditions.
AUTOMATIC TRANSMISSION (4L30-E) 7A-7
Page 882 of 1928

7A-10 AUTOMATIC TRANSMISSION (4L30-E)
WINTER DRIVE MODE
(1) Operation
The winter switch will operate when switched on after the all of following conditions are present.
Conditions:
a) The gear select position is "D" range only
b) Vehicle speed is 7mph (11 km/h) or less
c) Transmission oil temperature is 120°C (248°F) or less
d) Kick-down switch is off
e) Accelerator opening is at 8% or less.
(2) Cancel release
CD Cancellation by driver
a) Turning off the winter drive mode switch
b) Shifting select position to "3", "2", or "L"
(Winter drive mode is not canceled by selecting "D", "N", "R", or "P")
c) Ignition key is turned off
® Automatic cancellation
a) When vehicle runs at 21mph (34 km/h) or more for 1 second or more
b) When transmission oil temperature reaches 140°C (284°F) or above
Note: The mode returns
to normal drive mode automatically after the winter drive mode is canceled.
BACKUP MODE
If a major system failure occurs which could affect safety or damage the transmission under normal
vehicle operation, the diagnostic system detects the fault and overrides the TCM.
The "CHECK TRANS" light flashes to alert the driver, and the transmission must be manually shifted
as follows:
Select lever
position
D
Manual3
Manual2
Manual L
R
Gear Ratio Selected
4 (Fourth)
4 (Fourth)
3 (Third)
1 (First)
Reverse
Shifts are firmer to prevent clutch slip and consequent wear. The fault should be corrected as soon as
possible.
Page 883 of 1928

AUTOMATIC TRANSMISSION (4L30-E) 7 A-11
FUNCTIONS OF INPUT /OUTPUT COMPONENTS
Components Function
Speed sensor
Senses rotation
of output shaft and feeds the data to Transmission
(fixed
to transmission (T/M)) Control Module (TCM)
Throttle Senses the extent of throttle valve opening and the speed of the throttle
position sensor (TPS) valve lever motion to open the valve and feeds the data to TCM (fed to
(fixed to engine)
Engine Control Module (ECM) also)
I
Brake Switch (SW) Senses whether the driver has pressed the brake pedal or not and feeds
N (fixed
to brake pedal) the
information to TCM
p Kick-down SW (fixed to Senses whether the driver has pushed the accelerator pedal fully or not
u accelerator pedal) and feeds the information to TCM
T Mode
SW (fixed to T/M) Senses the select lever position and feeds the information to TCM
s Power drive SW Senses whether the driver has selected the power mode and feeds the
I (fixed to front console) information to TCM
G T/M
oil temp. sensor
Senses the T/M oil temperature and feeds the data to TCM
N Engine
coolant Senses the engine cooling water temperature and feeds the data to TCM
A temperature
SW (feeds the signal from ECM)
L
Engine speed
signal Feeds the signals monitoring engine speed to TCM from Ignition Control
Module
(fed to ECM also)
Air conditioning Senses whether the air conditioner has been switched on or not and
information feeds the information
to TCM
On-board diagnostic
input By monitoring the Ground (GND), the location of failure is shown on the
T/M
monitor lamp ("CHECK TRANS") by flashing the diagnostic trouble
code
Winter switch
Senses whether the driver has selected the winter mode, and feeds the
(fixed
to front console) information to TCM
Cruise
controller Downshift takes place when Overdrive OFF signal is received from auto
(Overdrive
OFF signal) cruise control unit
Shift
solenoid Selects shift point and gear position suited to the vehicle running con-s 1-2/3-4, 2-3
dition on the basis of TCM output 0 Band apply solenoid
Controls oil flow suited to the vehicle running condition on the basis of L
E TCM output
0 N
Torque
Converter Controls clutch engagement/disengagement suited to the vehicle
u 0 Clutch solenoid running condition on the basis of TCM output
T I Force motor Adjusts the oil pump delivery pressure to line pressure suited to the p D
(Pressure regulator vehicle running condition on the basis of TCM output u valve) T
Power drive mode lamp
Informs the driver whether the vehicle is in power mode or not
s Winter drive mode lamp Informs the driver whether the vehicle is in winter mode or not
I T/M monitor lamp Informs the driver of failure in the system. It also displays the self diagnosis
G
("CHECK TRANS") code.
N Data Link Connector
(DLC) When connected with TECH 1 or tester, can communicate the data for A
L function
check, etc. (fed to ECM also). When TECH 1 is not connected, can
communicate the
signal for torque management with ECM.
Self-diagnosis connector
When short-circuited with the bipolar connector, the T/M monitor lamp
displays
a failure by code.
ATF warning
lamp Lights when ATF oil temperature rises.
ABS signal When the select lever is at "Reverse" or "L" range, sends a signal to the
ABS controller as one of the ABS control conditions.
Page 885 of 1928

AUTOMATIC TRANSMISSION (4L30-E) 7A-13
NORMAL OPERATION OF 1994-95 4L30-E TRANSMISSION
1. TORQUE CONVERTER CLUTCH (TCC)
APPLICATION CONDITIONS:
Engine coolant temperature must be above 70°C
(158°F).
Moreover, TCC is ON in 2nd gear during kick down
operation when engine coolant temperature is
above
70°C (158°F).
Also,
TCC is always ON in 2nd, 3rd & 4th gear when
transmission oil temperature is above 140°C
(284°F).
2. ATF WARNING LAMP
The ATF warning lamp will be constantly on (not
flashing) if the transmission oil temperature is
above
145°C (293°F).
The ATF warning lamp goes off again when the
transmission
oil temperature is below 125°C
(257°F).
3. SPECIAL SHIFT PATTERN WHEN THE
ENGINE IS COLD:
A special shift pattern is activated when the engine
coolant temperature is below 70°C (158°F). (3-4
shifts
for example are delayed for small throttle
openings and will occur a few MPH higher)
4. SHIFT ALTERATION WITH TECH1
DIAGNOSTIC TOOL CONNECTED:
Shifts will be harsh when TECH1 is connected to
TCM: Connection of TECH1 automatically forces
maximum line pressure during shifts only.
Page 892 of 1928

7 A-20 AUTOMATIC TRANSMISSION (4L30-E)
CHECKING TRANSMISSION FLUID
LEVEL AND CONDITION
Checking fluid level and condition (color and odor)
at
regular intervals will provide early diagnosis
information about the transmission. This inform
ation may be used to correct a condition that, if not
detected early, could result in major transmission
repairs.
IMPORTANT: When new, automatic transmission
fluid is red in color. As the vehicle is driven, the
transmission
fluid will begin to look darker in color.
The
color may eventually appear light brown.
A DARK
brown color with burnt odor may indicate
excessive
fluid deterioration and signal a need for
fluid change.
FLUID LEVEL
When adding
or changing fluid, use only DEXRON
®-Ill.
Refer to the Maintenance and Lubrication (Section 0
of this manual) for maintenance information and
servicing
interval.
\f CAUTION: DO NOT OVERFILL
Overfilling will cause foaming, loss ~f fluid,
abnormal shifting and possible damage to
the transmission.
1. Start engine and drive vehicle until normal AfT
oil operating temperature is reached:
NOTE: The automatic transmission fluid level
must be checked with the vehicle at normal
A/T oil operating temperature: 75 TO 85°C
(167 TO 185°F) MEASURED WITH TECH1 SCAN
TOOL.
Temperature will greatly affect transmission
fluid level.
If the vehicle is not at normal AfT oil operating
temperature and the proper checking
procedures are
not followed, the result could
be a false reading of the fluid level indicator
and
an incorrect adjustment of the fluid level.
2. Park vehicle on level ground.
3. Move gear selector to "Park".
4. Apply parking brake and block wheels.
5. Allow vehicle to idle for 3 minutes with all
accessories turned off.
6. Check fluid level with engine running at idle:
Fluid should
be in "HOT" area on AfT dipstick
(Fig. 7A-6).
Check also color and condition (Refer to next
page.)
Hot
Cold ---IIU 0
0
Min
Dipstick
Fig. 7A-6
\f CAUTION:
DO NOT CHECK FLUID LEVEL UNDER THESE
CONDITIONS: •
At high ambient temperature above 30°C
(86°F).
Immediately after driving at sustained highway
speeds.
• In heavy city traffic during hot weather.
If vehicle is towing a trailer.
If the vehicle has been operated under these
conditions,
shut the engine off and allow the
vehicle to "cool" for thirty (30) minutes. After the
cool-down period, restart the vehicle and continue
from step 2 above.
'~I
......