2004 ISUZU TF SERIES fuel consumption

7A2-2 TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L)

Service Precaution
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL
RESTRAINT SYSTEM (SRS). REFER TO THE SRS
COMPONENT AND WIRING LOCATION VIEW IN
ORDER TO DETERMINE WHETHER YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING. WHEN YOU
ARE PERFORMING SERVICE ON OR NEAR THE
SRS COMPONENTS OR THE SRS WIRING, REFE
R
TO THE SRS SERVICE INFORMATION. FAILURE TO
FOLLOW WARNINGS COULD RESULT IN
POSSIBLE AIR BAG DEPLOYMENT, PERSONAL
INJURY, OR OTHERWISE UNNEEDED SRS SYSTEM
REPAIRS.
CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, o
r
other corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener.
When you install fasteners, use the correct
tightening sequence and specifications. Following
these instructions can help you avoid damage to
parts and systems.
General Description
The AW30-40LE 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.
 3rd Start mode –Starts in 3rd gear to reduce
slippage on ice or snow.
 Power mode has a delayed up shift 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 diagnosis
in a short time when the control system fails, thus
improving serviceability.
The major features of AW30-40LE 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 hydraulic
pressure for clutch, band brake as well as
transmission so that shift feeling is improved.
 Two sets of planetary gears reduce friction of powe
r
train.
Also, a lockup mechanism in the torque converter
reduces fuel consumption.
 Wide gear ratio and high torque rate of torque
converter provide excellent starting performance.

TRANSMISSION CONTROL SYSTEM (AW30–40LE) (V6 3.5L) 7A2-55

DTC P0743 (FLASHING CODE 33) Torque Converter Clutch Electrical


RUW37ALF000601
Circuit Description
The lock-up solenoid SL of the torque converter clutch
(TCC) controls the lock-up clutch by a signal according
to the lock-up range judgment of the TCM when the
vehicle runs.
This function can improve the fuel consumption to
almost the same extent as the manual transmission.
The lock-up solenoid SL is put into B+ by the TCM, so
that the solenoid is actuated with the result of lock-up.
Condition for setting the DTC
The TCM detects following conditions both "Condition
1" and "Condition 2" occur 2 times or more than it.
Condition 1 ("GND short"):

Voltage at connector pin is 0V for 0.3 sec
continuously when solenoid is “ON".
Condition 2 ("Open or IG short"):

Voltage at connector pin is ignition voltage for 0.5
sec continuously when solenoid is “OFF".
Action Taken When The DTC Sets

No lock-up control.
 The TCM fixes to 1st gear when the vehicle speed is
less than 6 mph.

Check Trans ON.

DTC stored.

DIAGNOSIS (JR405E) 7A2-5
PAGE
NO. Z3: MODE LAMP (POWER DRIVE OR 3RD START) LIGHTS UP WHEN
THE POWER MODE OR 3RD START MODE IS TURNED OFF .................................. 7A2-137
NO. Z4: OIL TEMPERATURE WARNING LAMP LIGHTS UP ...................................... 7A2-137
NO. Z5: SELECT LEVER FEELING IS FAULTY. .......................................................... 7A2-137
NO. Z6: POOR FUEL CONSUMPTION ......................................................................... 7A2-138
NO. Z7: PATTERN SELECT SWITCH IS FAULTY........................................................ 7A2-138
NO. Z8: OIL IS SPLASHED DURING THE RUNNING .................................................. 7A2-138
NO. Z9: ABNORMAL SMELL ........................................................................................ 7A2-138
NO. Z10: ATF QUANTITY IS LOW OR HIGH ................................................................ 7A2-138
NO. Z11: ABNORMAL OIL PRESSURE........................................................................ 7A2-139
NO. Z12: REVERSE BUZZER DOES NOT RING .......................................................... 7A2-139
STALL TEST .................................................................................................................. 7A2-140
LINE PRESSURE TEST................................................................................................. 7A2-141
TIME LAG TEST............................................................................................................. 7A2-143
TEST DRIVE................................................................................................................... 7A2-144
SHIFT POINT CHART .................................................................................................... 7A2-147
SHIFT POINT DIAGRAM................................................................................................ 7A2-149
TCM VOLTAGE CHECK ................................................................................................ 7A2-154

DIAGNOSIS (JR405E) 7A2-91
SYMPTOM DIAGNOSIS

Symptom Condition Description
Oil Leak Breather Oil leaks from breather. J1
Between engine and converter housing Oil leaks between engine and converter
housing. J2
Between converter housing and main caseOil leaks between converter housing and
main case. J3
Between main case and rear housing Oil leaks between main case and rear
housing. J4
Oil pan Oil leaks from oil pan. J5
Manual shaft oil seal Oil leaks from manual shaft oil seal. J6
Oil cooler pipe Oil leaks from oil cooler pipe joint. J7
Other Transmission overheat You smell the transmission burning. Z1

The transmission smokes.
Mode lamp does not light up when the
power mode or 3rd start mode is turned on
The mode lamp on the instrument panel
does not light up though the power mode or
3rd start mode is turned on with the ignition
switch in ON position.
Z2
Mode lamp lights up when the power mode
or 3rd start mode is turned off
The mode lamp on the instrument panel
lights up though the power mode or 3rd start
mode is turned off with the ignition switch in
ON position.
Z3
Oil temperature warning lamp lights up Sometimes, the oil temperature warning
lamp lights up. Z4
Select lever feeling is faulty Select lever feeling is faulty. Z5
Poor fuel consumption Poor fuel consumption. Z6
Pattern select switch is faulty Shift pattern does not change though the
pattern select switch is turned on. Z7
Oil is splashed during the running Oil is splashed during the running. Z8
Abnormal smell Abnormal smell. Z9
Oil quantity is low or high Oil quantity is low or high. Z10
Abnormal oil pressure Oil pressure is low or high. Z11
Reverse buzzer does not ring Reverse buzzer does not ring in R range. Z12

7A2-138 DIAGNOSIS (JR405E)
No. Z6: Poor Fuel Consumption

Description:

Poor fuel consumption.

Diagnosis Hints:

Basically same causes as "No. C1 - C8: Engine races up (slip) by shift up or shift down" are considered.



No. Z7: Pattern Select Switch is Faulty

Description:

Shift pattern does not change though the pattern select switch is turned on.

Possible Cause:

Faulty mode select switch is considered.



No. Z8: Oil is Splashed During the Running

Description:

Oil is splashed during the running

Possible Cause:

ATF quantity is too high.



No. Z9: Abnormal Smell

Description:

Abnormal smell.

Diagnosis Hints:

Basically a trouble in the AT main unit.



No. Z10: ATF Quantity is Low or High

Description:

Oil quantity is low or high.

Possible Cause:

In case of oil level is high.
ATF temperature is low when ATF quantity is checked.

In case of oil level is low.
ATF leaks is considered. Check the AT main unit and cooler circuit.