AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-19
ROAD TESTM1231007800407
Check using the following procedures.
STEP CONDITION
BEFORE
TEST/OPERATIONTEST/OPERATION STANDARD INSPECTION
ITEMINSPECTION
PROCEDURE
PA G E
1 Ignition switch:
(LOCK) OFFIgnition switch
(1) ONData list No.8
(1) Control Relay
Voltage [V]A/T Control
relay
output
voltageA/T Control
relay system
(P.23A-207).
2 Ignition switch:
ON
Engine: Stopped
Transmission
range: PTransmission range
(1) P, (2) R, (3) N, (4)
DData list No.34
(1) P, (2) R, (3) N, (4)
DTransmissi
on range
switchTransmission
range switch
system
(P.23A-97,
P.23A-119).
Transmission range
(1) D (1st gear)
(2) Select the sport
mode (1st gear)
(3) Upshift and hold
the selector lever in
that position (2nd
gear)
(4) Downshift and
hold the selector
lever in that position
(1st gear)Data list No.27
(1) OFF, (2) ON, (3)
ON, (4) ON
Data list No.28
(1) OFF, (2) OFF, (3)
ON, (4) OFF
Data list No.29
(1) OFF, (2) OFF, (3)
OFF, (4) ONSelect
switch and
Shift switchShift switch
assembly
system
(P.23A-252).
Brake pedal
(1) Depressed
(2) ReleasedData list No.19
(1) ON
(2) OFFSto pl amp
switchSt o pla mp
switch system
(P.23A-89).
3 Ignition switch:
ST
Engine: StoppedCranking test with
lever in P or N rangeCranking should be
possibleCranking Engine does
not crank
(P.23A-218).
4 Engine warming
upDrive for 15 minutes
or more so that the
transmission fluid
temperature
becomes 70
90CData list No.7
Gradually rises to 70
90CTransmissi
on fluid
temperatur
e sensorTransmission
fluid
temperature
sensor system
(P.23A-36,
P.23A-47).
5 Engine: Idling
Transmission
range: NBrake pedal (Retest)
(1) Depressed
(2) ReleasedData list No.19
(1) ON
(2) OFFSto pl amp
switchSt o pla mp
switch system
(P.23A-89).
Transmission range
(1) N
D
(2) N
RShould be no
abnormal shift
shocks
Time delay when
engaging should be
within 2 secondsMalfunction
when
startingEngine stalls
when moving
selector lever
from N to D or
N to R
(P.23A-227).
AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-25
TORQUE CONVERTER STALL TESTM1231005400362
This test measures the maximum engine speed when the
selector lever is in the "D" or "R" position and the torque con-
verter stalls. This tests the operation of the torque converter,
starter motor and one-way clutch operation, as well as the hold-
ing performance of the clutches and brakes in the transmission.
Do not let anyone stand in front of or behind the vehi-
cle while this test is performed.
1. Check the transmission fluid level and temperature. Check
the engine coolant temperature.
Transmission fluid level: At the "HOT" mark on the dipstick
Transmission fluid temperature: 70 80C
Engine coolant temperature: 80 100C
NOTE: Measures transmission fluid temperature with
diagnostic tool MB991958 (MUT-III sub assembly).
2. Check both rear wheels.
3. Pull the parking brake lever on, with the brake pedal fully
depressed.
4. Start the engine. 9 Transmission
range: N (on a
flat and straight
road)Monitor data list
No.22 and No.23
with the diagnostic
tool MB991958
(MUT-III sub
assembly)
(1) Move selector
lever to R range,
drive at constant
speed of 10 km/hThe ratio between
data list No.22 and
No.23 should be the
same as the gear
ratio when reversing.Does not
shiftInput shaft
speed sensor
system
(P.23A-55).
Output shaft
speed sensor
system
(P.23A-72).
Reverse gear
incorrect ratio
(P.23A-196).
STEP CONDITION
BEFORE
TEST/OPERATIONTEST/OPERATION STANDARD INSPECTION
ITEMINSPECTION
PROCEDURE
PA G E
AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-26
The throttle should not be fully open for any more than
five seconds.
If you repeat the stall test when the transmission fluid
temperature is greater than 80
C, move the selector
lever to the "N" position and let the engine run at
approximately 1,000 r/min for at least one minute. Wait
until the transmission fluid temperature returns to 80
C
or less.
5. Move the selector lever to the "D" position. Fully depress the
accelerator pedal and read the maximum engine speed at
this time.
Standard value: Stall speed: 2,100
2,600 r/min
6. Move the selector lever to the "R" position. Fully depress the
accelerator pedal and read the maximum engine speed.
Standard value: Stall speed: 2,100
2,600 r/min
TORQUE CONVERTER STALL TEST JUDGMENT
RESULTS
1. Stall speed is too high in both "D" and "R" range
Malfunction of the torque converter (Slippage on the splines
of the torque converter and the input shaft)
Low line pressure
Low-reverse brake slippage and malfunction of the one-way
clutch
2. Stall speed is too high in "D" range only
Underdrive clutch slippage
3. Stall speed is too high in "R" range only
Reverse clutch slippage
4. Stall speed is too low in both "D" and "R" ranges
Malfunction of the torque converter (Slippage of the
one-way clutch)
Insufficient engine output
HYDRAULIC PRESSURE TESTSM1231005500392
The transmission fluid temperature should be between 70
80C during the test.
1. Check the transmission fluid level and temperature. Check
engine coolant temperature.
Transmission fluid level: "HOT" mark on the dipstick
Transmission fluid temperature: 70 80C
Engine coolant temperature: 80 100C
2. Raise the vehicle so that the wheels are free to turn.
AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-32
HYDRAULIC CIRCUITM1231008800336
OVERVIEW
1. REVERSE CLUTCH
2. LOW-REVERSE BRAKE
3. SECOND BRAKE
4. UNDERDRIVE CLUTCH
5. OVERDRIVE CLUTCH
6. RED CLUTCH
7. DIR CLUTCH
8. TORQUE CONVERTER CLUTCH
9. FAIL SAFE VALVE A
10. FAIL SAFE VALVE B
11. FAIL SAFE VALVE C
12. SWITCH VALVE
13. TRANSMISSION FLUID COOLER
14. TORQUE CONVERTER CLUTCH CONTROL
VA LV E
15. LOW-REVERSE PRESSURE CONTROL VALVE
16. SECOND PRESSURE CONTROL VALVE
17. UNDERDRIVE PRESSURE CONTROL VALVE
18. OVERDRIVE PRESSURE CONTROL VALVE 19. RED PRESSURE CONTROL VALVE
20. TORQUE CONVERTER CLUTCH SOLENOID
VA LV E
21. LOW-REVERSE SOLENOID VALVE
22. SECOND SOLENOID VALVE
23. UNDERDRIVE SOLENOID VALVE
24. OVERDRIVE SOLENOID VALVE
25. RED SOLENOID VALVE
26. TORQUE CONVERTER PRESSURE
CONTROL VALVE
27. REGULATOR VALVE
28. MANUAL VALVE
29. OIL STRAINER
30. OIL FILTER
31. OIL PUMP
32. OIL FILTER
33. RELIEF VALVE
34. OIL PAN
AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-33
LINE PRESSURE ADJUSTMENTM1231001700361
1. Drain the transmission fluid.
NOTE: The hydraulic pressure test must be performed
before attempting any adjustments.
2. Remove the valve body cover.
3. Turn the adjusting screw shown in the illustration to adjust
the line pressure to the standard value in "D" range 1st or
2nd gear. The pressure increases when the screw is turned
counterclockwise approximately 35 kPa for each turn.
NOTE: When adjusting the line pressure, adjust to the mid-
dle of the standard value range.
Standard value: 980
1050 kPa
4. Install the valve body cover. Pour in the standard volume of
automatic transmission fluid.
5. Repeat the hydraulic pressure test. (Refer to P.23A-26).
Readjust the line pressure if necessary.
AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-34
DIAGNOSTIC TROUBLE CODE CHARTM1231007900330
During diagnosis, a DTC code associated with
other system may be set when the ignition switch
is turned on with connector(s) disconnected. On
completion, confirm all systems for DTC code(s).
If DTC code(s) are set, erase them all.
NOTE: The A/T diagnostic trouble codes are the codes which are set when item "A/T" is selected on
diagnostic tool MB991958 (MUT-III sub assembly). However, the some codes above indicate failure in the
MPI system.A/T DTC
NO.DIAGNOSIS ITEM REFERENCE
PA G E
P0713 Transmission fluid temperature sensor system Open circuit
P.23A-36
P0712 Short circuit
P.23A-47
P0715 Input shaft speed sensor system Short circuit/open circuit
P.23A-55
P0720 Output shaft speed sensor system Short circuit/open circuit
P.23A-72
Stoplamp switch systemShort circuit
P.23A-89
P0705 Transmission range switch system Open circuit
P.23A-97
Short circuit
P.23A-119
P0753 Low-reverse solenoid valve system Short circuit/open circuit
P.23A-133
P0758 Underdrive solenoid valve system Short circuit/open circuit
P.23A-144
P0763 Second solenoid valve system Short circuit/open circuit
P.23A-154
P0768 Overdrive solenoid valve system Short circuit/open circuit
P.23A-164
P0773 Reduction (RED) solenoid valve system Short circuit/open circuit
P.23A-174
P0743 Damper clutch control (DCC) solenoid valve
systemShort circuit/open circuit
P.23A-185
P0731 1st gear incorrect ratio
P.23A-196
P0732 2nd gear incorrect ratio
P.23A-196
P0733 3rd gear incorrect ratio
P.23A-196
P0734 4th gear incorrect ratio
P.23A-196
P0735 5th gear incorrect ratio
P.23A-196
P0736 Reverse gear incorrect ratio
P.23A-196
P0741 Damper clutch control (DCC) system Defective system
P.23A-201
P0742 Clutch stuck on
P.23A-204
P1751 A/T control relay system Short circuit to ground/open
circuitP.23A-207
AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-36
DIAGNOSTIC TROUBLE CODE PROCEDURES
(P0713): Transmission Fluid Temperature Sensor System (Open Circuit)
.
CIRCUIT OPERATION
The A/T-ECU connector B-22 (terminal 6) applies
5 volts to the transmission fluid temperature sen-
sor output terminal (terminal 1).
The transmission fluid temperature sensor circuit
is grounded to the A/T-ECU connector B-22 (ter-
minal 12).
When the transmission fluid temperature is cold,
the transmission fluid temperature sensor resis-
tance is high. When the transmission fluid tem-
perature is hot, the transmission fluid
temperature sensor resistance is low.
.
DTC SET CONDITIONS
Check Conditions
Engine speed: 1,000 r/min or more.
Output speed: 1,000 r/min or more.
Accumulated time in above condition: 10 min-
utes.
Judgement Criteria
Transmission fluid temperature sensor voltage:
4.5 volts or more. (1 second)
.
OBD-II DRIVE CYCLE PATTERN
Start the engine, drive at 60 km/h or more for 15 min-
utes in total.
.
TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CODE TO BE
SET ARE:)
Malfunction of the transmission fluid temperature
sensor circuit
Damaged harness or connector
Malfunction of the A/T-ECUCircuit drawings
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Refer to component locations GROUP-70
DIAGNOSIS
Required Special Tool:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-37
STEP 1. Using diagnostic tool MB991958, check data list
item 7: Transmission Fluid Temperature Sensor.
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect diagnostic tool MB991958 to the data link
connector.
(2) Start the engine.
(3) Set diagnostic tool MB991958 to the data reading mode.
Item 7: Transmission Fluid Temperature Sensor.
When the engine is cool: Diagnostic tool display is
almost equal to the ambient temperature (atmo-
spheric temperature)
NOTE: Set diagnostic tool MB991958 to the Engine
MPI data list reading mode for item number 5, Intake
Air Temperature (IAT) Sensor and note the tempera-
ture measurement. When the engine is cool, the
temperature should be almost equal to the ambient
temperature (atmospheric temperature), and the IAT
sensor measurement should be approximately the
same as the Transmission Fluid Temperature Sen-
sor.
When the engine is warm, at approximately running
temperature: 70
80C.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunction P.00-14.
NO : Go to Step 2.