AT-36
TROUBLE DIAGNOSIS
How to Perform Trouble Diagnoses for Quick and Accurate RepairBCS000ZZ
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor, accelera-
tor pedal position sensor or PNP switch and provides shift control or
lock-up control via A/T solenoid valves.
Input and output signals must always be correct and stable in the
operation of the A/T system. The A/T system must be in good oper-
ating condition and be free of valve seizure, solenoid valve malfunc-
tion, etc.
It is much more difficult to diagnose a malfunction that occurs inter-
mittently rather than continuously. Most intermittent malfunctions are
caused by poor electric connections or improper wiring. In this case,
careful checking of suspected circuits may help prevent the replace-
ment of good parts.
A visual check only, may not find the cause of the malfunctions. A
road test with CONSULT-II or a circuit tester connected should be
performed. Follow the AT- 3 7 , "
WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a drivability complaint. The customer
can supply good information about such malfunctions, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “DIAGNOSTIC WORKSHEET” like the
example (AT- 3 8 , "
DIAGNOSTIC WORKSHEET" ) should be used.
Start your diagnosis by looking for “conventional” malfunctions first.
This will help troubleshoot drivability malfunctions on an electroni-
cally controlled engine vehicle.
Also check related Service bulletins for information.
SAT631IA
SAT632I
SEF234G
TROUBLE DIAGNOSIS
AT-39
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Diagnostic Worksheet
1.❏ Read the Fail-safe and listen to customer complaints.AT- 3 4, AT- 3 8
2.❏ Check A/T fluidAT- 1 4❏ Leakage (Follow specified procedure)
❏ Fluid condition
❏ Fluid level
3.❏ Perform “STALL TEST” and “LINE PRESSURE TEST”.AT- 4 3
,
AT- 4 6
❏ “STALL TEST” — Mark possible damaged components/others.
❏ Torque converter one-way clutch
❏ Reverse clutch
❏ Forward clutch
❏ Overrun clutch
❏ Forward one-way clutch❏ Low & reverse brake
❏ Low one-way clutch
❏ Engine
❏ Line pressure is low
❏ Clutches and brakes except high clutch and
brake band are OK
❏ “LINE PRESSURE TEST” — Suspected parts:
4.❏ Perform “Road Test”.AT- 4 8
4-1.“Check Before Engine is Started”AT- 4 8
❏ AT-173, "A/T CHECK Indicator Lamp Does Not Come On" .
❏ Perform self-diagnostics. Enter checks for detected items. AT- 6 9
, AT- 7 6 .
❏ AT-133, "
CAN COMMUNICATION LINE" .
❏ AT-80, "
VEHICLE SPEED SENSOR·A/T (REVOLUTION SENSOR)" .
❏ AT-86, "
VEHICLE SPEED SENSOR MTR" .
❏ AT-120, "
TURBINE REVOLUTION SENSOR" .
❏ AT-90, "
SHIFT SOLENOID VALVE A" .
❏ AT-95, "
SHIFT SOLENOID VALVE B" .
❏ AT-100, "
OVERRUN CLUTCH SOLENOID VALVE" .
❏ AT-105, "
TORQUE CONVERTER CLUTCH SOLENOID VALVE" .
❏ AT-110, "
BATT/FLUID TEMP SEN (A/T FLUID TEMP SENSOR CIRCUIT AND TCM POWER
SOURCE)" .
❏ AT-116, "
ENGINE SPEED SIGNAL" .
❏ AT-136, "
A/T 1ST GEAR FUNCTION" .
❏ AT-140, "
A/T 2ND GEAR FUNCTION" .
❏ AT-143, "
A/T 3RD GEAR FUNCTION" .
❏ AT-146, "
A/T 4TH GEAR FUNCTION" .
❏ AT-151, "
A/T TCC S/V FUNCTION (LOCK-UP)" .
❏ AT-126, "
LINE PRESSURE SOLENOID VALVE" .
❏ AT-156, "
CONTROL UNIT (RAM)" .
❏ AT-157, "
CONTROL UNIT (ROM)" .
4-2.“Check at Idle”AT- 4 8
❏ AT-175, "Engine Cannot Be Started in “P” and “N” Position" .
❏ AT-176, "
In “P” Position, Vehicle Moves Forward or Backward When Pushed" .
❏ AT-176, "
In “N” Position, Vehicle Moves" .
❏ AT-177, "
Large Shock. “N” → “R” Position" .
❏ AT-179, "
Vehicle Does Not Creep Backward in “R” Position" .
❏ AT-181, "
Vehicle Does Not Creep Forward in “D”, “3”, “2” or “1” Position" .
AT-40
TROUBLE DIAGNOSIS
4. 4-3.“Cruise Test”AT- 5 0
Part 1
❏ AT-182, "
Vehicle Cannot Be Started From D1" .
❏ AT-184, "
A/T Does Not Shift: D1 → D2 or Does Not Kickdown: D4 → D2" .
❏ AT-186, "
A/T Does Not Shift: D2 → D3" .
❏ AT-188, "
A/T Does Not Shift: D3 → D4" .
❏ AT-191, "
A/T Does Not Perform Lock-up" .
❏ AT-193, "
A/T Does Not Hold Lock-up Condition" .
❏ AT-195, "
Lock-up Is Not Released" .
❏ AT-195, "
Engine Speed Does Not Return To Idle (Light Braking D4 → D3 )" .
Part 2AT- 5 1
❏ AT-182, "Vehicle Cannot Be Started From D1" .
❏ AT- 1 8 4 , "
A/T Does Not Shift: D1 → D2 or Does Not Kickdown: D4 → D2" .
❏ AT-186, "
A/T Does Not Shift: D2 → D3" .
❏ AT-188, "
A/T Does Not Shift: D3 → D4" .
Part 3AT- 5 2
❏ AT-197, "A/T Does Not Shift: D4 → 33 , When A/T Selector Lever “D” → “3”" .
❏ AT-203, "
Vehicle Does Not Decelerate By Engine Brake (D4 → 33 )" .
❏ AT-198, "
A/T Does Not Shift: 33 → 22 , When Selector Lever “3” → “2” Position" .
❏ AT-205, "
Vehicle Does Not Decelerate By Engine Brake (33 → 22 )" .
❏ AT-200, "
A/T Does Not Shift: 22 → 11 , When Selector Lever “2” → “1” Position" .
❏ AT-208, "
Vehicle Does Not Decelerate By Engine Brake (22 → 11 )" .
❏ Perform self-diagnostics. Enter checks for detected items. AT- 6 9
, AT- 7 6 .
❏ AT-133, "
CAN COMMUNICATION LINE" .
❏ AT-80, "
VEHICLE SPEED SENSOR·A/T (REVOLUTION SENSOR)" .
❏ AT-86, "
VEHICLE SPEED SENSOR MTR" .
❏ AT-120, "
TURBINE REVOLUTION SENSOR" .
❏ AT-90, "
SHIFT SOLENOID VALVE A" .
❏ AT-95, "
SHIFT SOLENOID VALVE B" .
❏ AT-100, "
OVERRUN CLUTCH SOLENOID VALVE" .
❏ AT-105, "
TORQUE CONVERTER CLUTCH SOLENOID VALVE" .
❏ AT-110, "
BATT/FLUID TEMP SEN (A/T FLUID TEMP SENSOR CIRCUIT AND TCM POWER
SOURCE)" .
❏ AT-116, "
ENGINE SPEED SIGNAL" .
❏ AT-136, "
A/T 1ST GEAR FUNCTION" .
❏ AT-140, "
A/T 2ND GEAR FUNCTION" .
❏ AT-143, "
A/T 3RD GEAR FUNCTION" .
❏ AT-146, "
A/T 4TH GEAR FUNCTION" .
❏ AT-151, "
A/T TCC S/V FUNCTION (LOCK-UP)" .
❏ AT-126, "
LINE PRESSURE SOLENOID VALVE" .
❏ AT-156, "
CONTROL UNIT (RAM)" .
❏ AT-157, "
CONTROL UNIT (ROM)" .
5.❏ For self-diagnosis NG items, inspect each component. Repair or replace the damaged parts.
6.❏ Perform “Road Test”.AT- 4 8
7.❏ Perform the Diagnostic Procedures for all remaining items marked NG. Repair or replace the damaged parts.
Refer to the Symptom Chart when you perform the procedures. (The chart also shows some other possible
symptoms and the component inspection orders.)AT- 5 5
8.❏ Erase DTC from TCM and ECM memories.AT- 6 9AT- 7 9
TROUBLE DIAGNOSIS
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Inspections Before Trouble DiagnosisBCS00102
A/T FLUID CHECK
Fluid Leakage and Fluid Level Check
Inspect for A/T fluid leakage and check the A/T fluid level. Refer to AT- 1 4 , "Checking A/T Fluid" .
A/T Fluid Condition Check
Inspect the A/T fluid condition.
STALL TEST
Stall Test Procedure
1. Check ATF and engine oil levels. If necessary, add ATF and oil.
2. Drive vehicle for approximately 10 minutes or until ATF and
engine oil reach operating temperature.
3. Set parking brake and block wheels.
4. Install a tachometer where it can be seen by driver during test.
It is good practice to mark the point of specified engine
rpm on indicator.
5. Start engine, apply foot brake, and place selector lever in “D”
position.
Fluid status Conceivable Cause Required Operation
Varnished (viscous
varnish state)Clutch, brake
scorchedReplace the ATF and check the A/T
main unit and the vehicle for mal-
functions (wire harnesses, cooler
pipes, etc.)
Milky white or
cloudyWater in the ATFReplace the ATF and check for
places where water is getting in.
Large amount of
metal powder mixed
inUnusual wear of
sliding parts within
A/TReplace the ATF and check for
improper operation of the A/T.
SAT638A
ATF operating temperature: 50 - 80°C (122 - 176°F)
SAT647B
SCIA7463E
SCIA5703E
AT-46
TROUBLE DIAGNOSIS
LINE PRESSURE TEST
Line Pressure Test Ports
Location of line pressure test ports are shown in the figure.
Always replace pressure plugs as they are self-sealing
bolts.
Line Pressure Test Procedure
1. Check ATF and engine oil levels. If necessary, add ATF or
engine oil.
2. Drive vehicle for approx. 10 minutes or until engine oil and ATF
reach operating temperature.
3. Install oil pressure gauge to corresponding line pressure test
port.
4. Set parking brake and block wheels.
SCIA3332E
ATF operating temperature: 50 - 80°C (122 -176°F)
SAT647B
SCIA4845E
SCIA7463E
AT-48
TROUBLE DIAGNOSIS
Road TestBCS00103
DESCRIPTION
The purpose of the test is to determine overall performance of A/T and analyze causes of malfunctions.
The road test consists of the following three parts:
1. Check before engine is started. Refer to AT- 4 8
.
2. Check at idle. Refer to AT- 4 8
.
3. Cruise test
Inspection all the item from Part 1 to Part 3. Refer to AT- 5 0 , AT- 5 1 and AT- 5 2 .
Before road test, familiarize yourself with all test procedures and items to check.
Perform tests on all items until specified symptom is found. Troubleshoot the items which are checked out
to be no good after road test. Refer to the following.
Refer to AT- 6 7 , "
CONSULT-II Function (A/T)" , AT- 7 6 , "Diagnostic Procedure Without CONSULT-II" and
AT- 1 6 8 , "
TROUBLE DIAGNOSIS FOR SYMPTOMS" .
Check Before Engine Is StartedBCS00104
1. CHECK A/T CHECK INDICATOR LAMP
1. Park vehicle on flat surface.
2. Move selector lever to “P” position.
3. Turn ignition switch OFF. Wait at least 5 seconds.
4. Turn ignition switch ON. (Do not start engine.)
Does A/T CHECK indicator lamp come on for about 2 seconds?
YES >> 1. Turn ignition switch OFF.
2. Perform self-diagnosis and note NG items.
Refer to AT- 6 9 , "
SELF-DIAGNOSTIC RESULT MODE" , AT- 7 6 , "Diagnostic Procedure Without
CONSULT-II" .
3. Go to AT- 4 8 , "
Check at Idle" .
NO >> Stop “Road Test”. Go to AT- 1 7 3 , "
A/T CHECK Indicator Lamp Does Not Come On" .
Check at IdleBCS00105
1. CHECK ENGINE START
1. Park vehicle on flat surface.
2. Move selector lever to “P” or “N” position.
3. Turn ignition switch OFF.
4. Turn ignition switch to “START” position.
Is engine started?
YES >> GO TO 2.
NO >>
Stop “Road Test”. Mark the box on the AT- 3 8 , "DIAGNOSTIC WORKSHEET" .
Go to AT- 1 7 5 , "Engine Cannot Be Started in “P” and “N” Position" .
2. CHECK ENGINE START
1. Turn ignition switch ON. (Do not start engine.)
2. Move selector lever to “R”, “D”, “3”, “2” or “1” position.
3. Turn ignition switch to “START” position.
Is engine started?
YES >>Stop “Road Test”. Mark the box on the AT- 3 8 , "DIAGNOSTIC WORKSHEET" .
Go to AT- 1 7 5 , "Engine Cannot Be Started in “P” and “N” Position" .
NO >> GO TO 3.
TROUBLE DIAGNOSIS
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3. CHECK VEHICLE MOVE
1. Move selector lever to “P” position.
2. Turn ignition switch OFF.
3. Release parking brake.
4. Push vehicle forward or backward.
Does vehicle move when it is pushed forward or backyard?
YES >>Mark the box AT- 1 7 6 , "In “P” Position, Vehicle Moves Forward or Backward When Pushed" on
the AT- 3 8 , "
DIAGNOSTIC WORKSHEET" .
Continue “Road Test”.
NO >> GO TO 4.
4. CHECK VEHICLE MOVE
1. Apply parking brake.
2. Start engine.
3. Move selector lever to “N” position.
4. Release parking brake.
Does vehicle move forward or backward?
YES >>Mark the box AT- 1 7 6 , "In “N” Position, Vehicle Moves" on the AT- 3 8 , "DIAGNOSTIC WORK-
SHEET" .
Continue “Road Test”.
NO >> GO TO 5.
5. CHECK SHIFT SHOCK
1. Apply foot brake.
2. Move selector lever to “R” position.
Is there large shock when changing from
“N” to “R” position?
YES >>Mark the box AT- 1 7 7 , "Large Shock. “N” → “R” Position" on the AT- 3 8 , "DIAGNOSTIC WORK-
SHEET" .
Continue “Road Test”.
NO >> GO TO 6.
6. CHECK VEHICLE MOVE
Release foot brake for several seconds.
Does vehicle creep backward when foot brake is released?
YES >> GO TO 7.
NO >>
Mark the box AT- 1 7 9 , "Vehicle Does Not Creep Backward in “R” Position" on the AT- 3 8 , "DIAG-
NOSTIC WORKSHEET" .
Continue “Road Test”.
7. CHECK VEHICLE MOVE
Move selector lever to “D”, “3”, “2” and “1” positions and check if vehicle creeps forward.
Does vehicle creep forward in all four positions?
YES >> Go to AT- 5 0 , "Cruise Test — Part 1" .
NO >>
Mark the box AT- 1 8 1 , "Vehicle Does Not Creep Forward in “D”, “3”, “2” or “1” Position" on the
AT- 3 8 , "
DIAGNOSTIC WORKSHEET" .
Continue “Road Test”.
AT-50
TROUBLE DIAGNOSIS
Cruise Test — Part 1BCS00106
1. CHECK STARTING GEAR (D1 ) POSITION
1. Drive vehicle for approximately 10 minutes to warm engine oil and ATF up to operating temperature.
2. Park vehicle on flat surface.
3. Move selector lever to “P” position.
4. Start engine.
5. Move selector lever to “D” position.
6. Accelerate vehicle by constantly depressing accelerator pedal half-way.
Read gear position. Refer to AT- 7 0 , "
DATA MONITOR MODE" .
Does vehicle start from D
1 ?
YES >> GO TO 2.
NO >>
Mark the box AT- 1 8 2 , "Vehicle Cannot Be Started From D1" on the AT- 3 8 , "DIAGNOSTIC
WORKSHEET" .
Continue “Road Test”.
2. CHECK SHIFT-UP (D1 TO D2 )
Check shift-up (D
1 to D2 ).
Specified speed when shifting from D
1 to D2 (Throttle position: half throttle). Refer to AT- 5 4 , "Vehicle Speed
Which Gear Shifting Occurs" .
Read gear position, throttle opening and vehicle speed. Refer to AT- 7 0 , "
DATA MONITOR MODE" .
Does A/T shift from D
1 to D2 at the specified speed?
YES >> GO TO 3.
NO >>
Mark the box AT- 1 8 4 , "A/T Does Not Shift: D1 → D2 or Does Not Kickdown: D4 → D2" on the
AT- 3 8 , "
DIAGNOSTIC WORKSHEET" .
Continue “Road Test”.
3. CHECK SHIFT-UP (D2 TO D3 )
Check shift-up (D
2 to D3 ).
Specified speed when shifting from D
2 to D3 (Throttle position: half throttle). Refer to AT- 5 4 , "Vehicle Speed
Which Gear Shifting Occurs" .
Read gear position, throttle opening and vehicle speed. Refer to AT- 7 0 , "
DATA MONITOR MODE" .
Does A/T shift from D
2 to D3 at the specified speed?
YES >> GO TO 4.
NO >>
Mark the box AT- 1 8 6 , "A/T Does Not Shift: D2 → D3" on the AT- 3 8 , "DIAGNOSTIC WORK-
SHEET" .
Continue “Road Test”.
4. CHECK SHIFT-UP (D3 TO D4 )
Check shift-up (D
3 to D4 ).
Specified speed when shifting from D
3 to D4 (Throttle position: half throttle). Refer to AT- 5 4 , "Vehicle Speed
Which Gear Shifting Occurs" .
Read gear position, throttle opening and vehicle speed. Refer to AT- 7 0 , "
DATA MONITOR MODE" .
Does A/T shift from D
3 to D4 at the specified speed?
YES >> GO TO 5.
NO >>
Mark the box AT- 1 8 8 , "A/T Does Not Shift: D3 → D4" on the AT- 3 8 , "DIAGNOSTIC WORK-
SHEET" .
Continue “Road Test”. ATF operating temperature: 50 - 80°C (122 - 176°F)