AUTOMATIC TRANSMISSION (4 A/T) 7B-13
DIAGNOSIS
This vehicle is equipped with an electronic transmission control system, which controls the automatic shift up
and shift down timing, etc. suitably to vehicle driving conditions.
When diagnosing a trouble in the transmission including this system, follow “AUTOMATIC TRANSMISSION
DIAGNOSTIC FLOW TABLE” given below to obtain correct result smoothly.
AUTOMATIC TRANSMISSION DIAGNOSTIC FLOW TABLE
NOTE:
For the details of each step, refer to the following pages.
Step Action Yes No
1 Customer Complaint Analysis
1) Perform customer complaint analysis refer-
ring to the following page.
Was customer complaint analysis performed
according to instruction on the following page?Go to Step 2. Perform customer com-
plaint analysis.
2 Diagnostic Trouble Code (DTC) Check, Record
and Clearance
1) Check for DTC referring to the following
page.
Is there any DTC(s)?1) Print DTC or write it
down and clear it by
referring to “DTC
CLEARANCE” in this
section.
2) Go to Step 3.Go to Step 4.
3 Visual Inspection
1) Perform visual inspection referring to the fol-
lowing page.
Is there any faulty condition?1) Repair or replace mal-
function part.
2) Go to Step 11.Go to Step 5.
4 Visual Inspection
1) Perform visual inspection referring to the fol-
lowing page.
Is there any faulty condition?Go to Step 8.
5 Trouble Symptom Confirmation
1) Confirm trouble symptom referring to the fol-
lowing page.
Is trouble symptom identified?Go to Step 6. Go to Step 7.
6 Rechecking and Record of DTC.
1) Recheck for DTC referring to “DTC CHECK”
in this section.
Is there any DTC(s)?Go to Step 9. Go to Step 8.
7 Rechecking and Record of DTC.
1) Recheck for DTC referring to “DTC CHECK”
in this section.
Is there any DTC(s)?Go to Step 9. Go to Step 10.
7B-14 AUTOMATIC TRANSMISSION (4 A/T)
8 Automatic Transmission Basic Check and Trou-
ble Diagnosis Table
1) Check and repair according to “A/T BASIC
CHECK” and “TROUBLE DIAGNOSIS
TABLE” in this section.
Are check and repair complete?Go to Step 11. 1) Check and repair
malfunction part(s).
2) Go to Step 11.
9 Troubleshooting for DTC
1) Check and repair according to applicable
DTC Diagnostic Flow Table.
Are check and repair complete?
10 Check for Intermittent Problems
1) Check for intermittent problems referring to
the following page.
Is there any faulty condition?1) Repair or replace mal-
function part(s).
2) Go to Step 11.Go to Step 11.
11 Final Confirmation Test
1) Clear DTC if any.
2) Perform final confirmation test referring to
the following page.
Is there any problem symptom, DTC or abnor-
mal condition?Go to Step 6. End. Step Action Yes No
AUTOMATIC TRANSMISSION (4 A/T) 7B-15
1. CUSTOMER COMPLAINT ANALYSIS
Record details of the problem (failure, complaint) and how it occurred as described by the customer. For this
purpose, use of such a questionnaire form as shown below will facilitate collecting information to the point
required for proper analysis and diagnosis.
CUSTOMER QUESTIONNAIRE (EXAMPLE)
NOTE:
The above form is a standard sample. It should be modified according to conditions
characteristic of each market.
AUTOMATIC TRANSMISSION (4 A/T) 7B-17
8. AUTOMATIC TRANSMISSION BASIC CHECK AND TROUBLE DIAGNOSIS TABLE
Perform basic automatic transmission check according to the list below first. When the end of the list has been
reached, check the part of system suspected as a possible cause referring to “TROUBLE DIAGNOSIS TABLE”
and based on symptoms appearing on vehicle (symptoms obtained through steps of customer complaint analy-
sis, trouble symptom confirmation and/or A/T basic check) and repair or replace faulty parts, if any.
AUTOMATIC TRANSMISSION BASIC CHECK LIST
1) Power Supply Voltage Check
Check that the battery voltage is within 10 – 14 V at engine stop.
2) A/T Fluid Check
Check A/T fluid level and quality.
3) STALL TEST
Perform stall test. Refer to “STALL TEST” in this section for details.
4) LINE PRESSURE TEST
Perform line pressure test. Refer to “LINE PRESSURE TEST” in this section.
5) ROAD TEST
Perform road test to understand correctly the trouble area.
6) Electrical Harness and Coupler Check
Check the connection of the harness coupler. Check for the loose connection of the harness, loose connec-
tion of the terminals.
9. DIAGNOSTIC TROUBLE CODE FLOW TABLE
Based on the DTC indicated in STEP 6 and STEP 7 and referring to “DTC CHECK”, locate the cause of the
trouble, namely in a sensor, switch, wire harness, connector, actuator, TCM or other part and repair or replace
faulty parts.
10. CHECK FOR INTERMITTENT PROBLEM
Check parts where an intermittent trouble is easy to occur (e.g. wire harness, connector, etc.), referring to
“INTERMITTENT AND POOR CONNECTION” in Section 0A and related circuit of DTC recorded in Step 2.
11. FINAL CONFIRMATION TEST
Confirm that the problem symptom has gone and the automatic transmission is free from any abnormal condi-
tions. If what has been repaired is related to the malfunction DTC, clear the DTC once and perform test driving
and confirm that a normal code is indicated.
7B-18 AUTOMATIC TRANSMISSION (4 A/T)
TROUBLE DIAGNOSIS TABLE
TABLE 1 (ELECTRICAL)
NOTE:
For the inspection of throttle position sensor, refer to “TP SENSOR” in Section 6E.
Condition Possible Cause Correction
No up-shift
1st
→
→→ → 2nd
2nd
→
→→ → 3rdOutput shaft speed sensor or its circuit faulty Inspect output shaft speed sen-
sor.
Shift solenoid -D (No.4) (1st →
→→ →
2nd), -A
(No.1) (1st →
→→ →
3rd), -E (No.5) (2nd →
→→ →
3rd),
and/or its circuit faultyRepair or replace.
Throttle position sensor or its circuit faulty Inspect TP sensor.
TCM faulty Replace TCM.
3rd
→
→→ → 4th
Output shaft speed sensor or its circuit faulty Inspect output shaft speed sen-
sor.
Shift solenoid -B (No.2), -C (No.3) or its cir-
cuit faultyRepair or replace.
O/D CUT switch circuit faulty Refer to “O/D OFF SWITCH” in
this section and/or inspect its cir-
cuit.
Throttle position sensor or its circuit faulty Inspect TP sensor.
TCM faulty Replace TCM.
No down-shift
4th
→
→→ → 3rd
3rd
→
→→ → 2nd
2nd
→
→→ →1stShift solenoid -C (No.3) (4th →
→→ →
3rd), -D
(No.4) (2nd →
→→ →
1st), -A (No.1) (3rd →
→→ →
2nd), -B
(No.2) (4th →
→→ →
3rd), -E (No.5) (3rd →
→→ →
2nd) or
its circuit faultyRepair or replace.
Throttle position sensor or its circuit faulty Inspect TP sensor.
TCM fault Replace TCM.
Shift point too high or
too lowThrottle position sensor, output shaft speed
sensor or its circuit faultyInspect TP sensor and/or output
shaft speed sensor.
Vehicle does not move
Shift solenoid -A (No.1), -C (No.3), -D (No.4)
or its circuit faultyRepair or replace.
Excessive slip
Shift solenoid -A (No.1) to -E (No.5) or its cir-
cuit faultyRepair or replace.
Excessive shock at
N
→
→→ → D or N
→
→→ → RShift solenoid -A (No.1), -D (No.4), -E (No.5)
or its circuit faultyRepair or replace.
ISC circuit Inspect ISC circuit.
No lock-up or
No lock-up OFFTCC (lock-up) solenoid valve or its circuit
faultyRepair or replace.
Throttle position sensor or its circuit faulty Refer to “THROTTLE POSITION
SENSOR” in Section 6E.
Input shaft speed and/or output shaft speed
sensor or its circuit faulty.Refer to “ECT SENSOR” in Sec-
tion 6E.
Abnormal engine rev. signal or its circuit. Repair or replace.
ECM faulty Inspect ECM.
AUTOMATIC TRANSMISSION (4 A/T) 7B-19
TABLE 2 (MECHANICAL)
Condition Possible Cause Correction
Vehicle does not move
at any rangeManual valve faulty Clean or replace.
Primary regulator valve faulty Clean or replace.
No gear
change
1st
↔
↔↔ ↔ 2nd
Shift solenoid -D (No.4) and/or -E (No.5)
stuck Clean or replace.
2nd
↔
↔↔ ↔ 3rd
Shift solenoid -A (No.1), -C (No.3) and/or fail
valve No.1 stuckClean or replace.
3rd
↔
↔↔ ↔ 4th
Shift solenoid -B (No.2), -C (No.3) and/or fail
valve No.2 stuckClean or replace.
Harsh engagement
P, N
→
→→ → R
Front clutch accumulator faulty Clean or replace.
N
→
→→ → D
1st & 2nd brake accumulator faulty Clean or replace.
1st
→
→→ → 2nd at D
range or 2 rangeFront clutch accumulator faulty Clean or replace.
Shift solenoid -D (No.4) Clean or replace.
2nd
→
→→ → 3rd at D
rangeDirect clutch accumulator faulty Clean or replace.
Shift solenoid -E (No.5) Clean or replace.
3rd
→
→→ → 4th at D
rangeOverdrive brake accumulator faulty Clean or replace.
Shift solenoid -B (No.2) Clean or replace.
All gear change
Primary regulator valve faulty Clean or replace.
Excessive slip
(low line pressure)Primary regulator valve faulty Clean or replace.
Vehicle does not
move at
1st, 2nd, 3rd and
reverse gearRear clutch faulty Repair or replace.
Reverse gear
Reverse brake faulty Repair or replace.
2nd, 3rd and 4th
gearFront clutch faulty Repair or replace.
3rd and 4th gear
Direct clutch faulty Repair or replace.
1st and 2nd gear
1st & 2nd brake faulty Repair or replace.
4th gear
Overdrive brake faulty Repair or replace.
Any forward and
reverse gearParking lock pawl faulty Repair or replace.
Shock or engine stalls
when starting off and
stoppingTCC (lock-up clutch) faulty Inspect and replace as necessary.
TCC (lock-up) solenoid faulty Clean or replace.
Lock-up control valve faulty Clean or replace.
Lock-up signal valve faulty Clean or replace.
No up-shift
1st
→
→→ → 2nd
Front clutch faulty Repair or replace.
2nd
→
→→ → 3rd
Direct clutch faulty Repair or replace.
3rd
→
→→ → 4th
Overdrive brake faulty Repair or replace.
No engine
braking
2nd or 3rd gear
Front, rear or direct clutch or 1st & 2nd brake
faultyRepair or replace
L range 1st gear
Direct clutch or 1st & 2nd brake faulty Repair or replace.
No lock-up
Torque converter clutch faulty Inspect and replace as necessary.
Lock-up control valve faulty Clean or replace.
TCC (lock-up) solenoid faulty Clean or replace.
Secondary regulator valve faulty Clean or replace.
Signal valve faulty Clean or replace.
AUTOMATIC TRANSMISSION (4 A/T) 7B-37
DTC P0741 (DTC NO.29) TCC (LOCK-UP) SOLENOID PERFORMANCE OR STUCK OFF
Step Action Yes No
1Was “AUTOMATIC TRANSMISSION DIAG-
NOSTIC FLOW TABLE” performed?Go to Step 2. Go to “AUTOMATIC
TRANSMISSION DIAG-
NOSTIC FLOW TABLE”.
2 Check TCC (lock-up) solenoid referring to
“SHIFT SOLENOID VALVES” in this section.
Is it in good condition?Go to Step 3. Replace TCC (lock-up)
solenoid.
3 Check valve body for fluid passage clog, or
lock-up control valve, secondary regulator valve
or signal valve stuck, referring to “TRANSMIS-
SION UNIT REPAIR OVERHAUL” in this sec-
tion.
Are they in good condition?Go to Step 4. Faulty valve body.
4 Substitute a known-good torque converter and
recheck.
Is it OK?Torque converter mal-
function.Overhaul and repair auto-
matic transmission.
DTC DETECTING CONDITION
Difference between turbine rev. and engine rev. too close even though TCM ordered to turn OFF lock-up.
Difference between turbine rev. and engine rev. too wide even though TCM ordered to turn ON lock-up.
AUTOMATIC TRANSMISSION (4 A/T) 7B-41
DTC P1700 (DTC NO.32/33) THROTTLE POSITION SIGNAL INPUT MALFUNCTION
1. Throttle position (TP) sensor 4. TCM coupler (viewed from harness side)
2. ECM 5. ECM coupler (viewed from harness side)
3. TCM
DTC DETECTING CONDITION
NO or abnormal throttle opening signal inputted.
Step Action Yes No
1 Check DTC of “ENGINE DIAGNOSIS” referring
to Section 6.
Is there DTC related to throttle position sensor
detected?Inspect and repair refer-
ring to DTC flow table of
“ENGINE DIAGNOSIS” in
Section 6.Go to Step 2.
2 Is DTC No.33? Go to Step 4. Go to Step 3.
3 Is DTC No.32? Go to Step 5. Go to Step 5.
(When DTC is P1700.)
4 1) Turn ignition switch OFF and disconnect
ECM couplers.
2) Turn ignition switch ON and check voltage
between terminal “C41-21” of disconnected
harness side ECM coupler and body
ground.
Is it 10 – 14 V?Poor connection of termi-
nal “C41-21” of ECM cou-
pler.
If connection is OK, sub-
stitute a known-good
ECM and recheck.“PPL” wire open or poor
connection of terminal
“C43-8” of TCM coupler.
If wire and connection are
OK, substitute a known-
good TCM and recheck.