AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-23
Does not
shiftNo diagnostic
trouble code
(P.23A-244).
Input shaft
speed sensor
system
(P.23A-55).
Output shaft
speed sensor
system
(P.23A-72).
8 Use the
diagnostic tool
MB991958
(MUT-III sub
assembly) to
stop the
INVECS-II
function
Transmission
range: D (on a
flat and straight
road)(1) Accelerate from
1st gear to 5th gear.
(2) While driving at
60 km/h in 5th gear,
downshift to 4th gear
(3) While driving at
40 km/h in 4th gear,
downshift to 3rd gear
(4) While driving at
30 km/h in 3rd gear,
downshift to 2nd gear
(5) While driving at
20 km/h in 2nd gear,
downshift to 1st gearData list No.11
(1) 1st
2nd 3rd
4th 5th
(2) 5th
4th
(3) 4th
3rd
(4) 3rd
2nd
(5) 2nd
1stDoes not
shift from 1
to 2 or 2 to
1Low-reverse
solenoid valve
system
(P.23A-133).
Second
solenoid valve
system
(P.23A-154).
1st gear
incorrect ratio
(P.23A-196).
2nd gear
incorrect ratio
(P.23A-196).
Does not
shift from 2
to 3 or 3 to
2Second
solenoid valve
system
(P.23A-154).
Overdrive
solenoid valve
system
(P.23A-164).
2nd gear
incorrect ratio
(P.23A-196).
STEP CONDITION
BEFORE
TEST/OPERATIONTEST/OPERATION STANDARD INSPECTION
ITEMINSPECTION
PROCEDURE
PA G E
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-28
STANDARD HYDRAULIC PRESSURE TABLE
NOTE: When the torque converter pressure is measured, the engine speed should be 1,500 r/min or less.
HYDRAULIC PRESSURE TEST DIAGNOSIS TABLE
MEASUREMENT
CONDITIONSSTANDARD HYDRAULIC PRESSURE kPa
SELECT-
OR
LEVER
POS’N SHIFT
RANGE
POSITIO
NENGINE
SPEED
(r/min)UNDERDRIVE
CLUTCH
PRESSURE
[UD]REVERSE
CLUTCH
PRESSURE
[RV]OVERDRIVE
CLUTCH
PRESSURE
[OD]DIRECT
CLUTCH
PRESSURE
[DIR]LOW-
REVERSE
BRAKE
PRESSURE
[LR]SECOND
BRAKE
PRESSURE
[2ND]TORQUE
CONVERTER
PRESSURE
[DR]
P2,500260 360260 360
R Rev. 2,500
12701770 12701770 500 730
N
2,500260 360 220 360
Spo rt
mode1st 2,500 980
1050 980 1050 500 730
2nd 2,500 980
1050 980 1050 500 730
3rd 2,500 780
900 780 900 450 720
4th 2,500 780
900 780 900 780 880 450 720
5th 2,500
780 900 780 880 780 880 450 720
SYMPTOM PROBABLE CAUSE
All hydraulic pressures are high. Malfunction of the regulator valve
All hydraulic pressures are low. Malfunction of the oil pump
Clogged internal oil filter
Clogged oil cooler
Malfunction of the regulator valve
Malfunction of the relief valve
Incorrect valve body installation
Improperly installed solenoid valves
Damaged solenoid valve O-rings
Hydraulic pressure is abnormal
in reverse gear only.Malfunction of the regulator valve
Clogged orifice
Incorrect valve body installation
Hydraulic pressure is abnormal
in 3rd or 4th gear only.Malfunction of the overdrive solenoid valve
Malfunction of the overdrive pressure control valve
Malfunction of the regulator valve
Malfunction of the switch valve
Clogged orifice
Incorrect valve body installation
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