TM-100
< COMPONENT DIAGNOSIS >[CVT: RE0F09B]
P1778 STEP MOTOR - FUNCTION
P1778 STEP MOTOR - FUNCTION
DescriptionINFOID:0000000003849044
The step motor changes the step by turning 4 coils ON/OFF according to the signal from TCM. As a result,
the flow of line pressure to primary pulley is changed and pulley ratio is controlled.
This diagnosis item is detected when the electrical system is OK, but the mechanical system is NG.
This diagnosis item is detected when the state of the changing of the speed mechanism in the unit does not
operate normally.
DTC LogicINFOID:0000000003849045
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
CAUTION:
Always drive vehicle at a safe speed.
Before starting “DTC CONFIRMATION PROCEDURE”, confirm “Hi” or “Mid” or “Low” fixation by
“PRI SPEED” and “VEHICLE SPEED” on “Data Monitor”.
If hi-geared fixation occurred, go to TM-100, "
Diagnosis Procedure".
NOTE:
Immediately after performing any “DTC CONFIRMATION PROCEDURE”, always turn ignition switch OFF.
Then wait at least 10 seconds before performing the next test.
1.CHECK DTC DETECTION
With CONSULT-III
1. Turn ignition switch ON.
2. Select “Data Monitor” mode for “TRANSMISSION”.
3. Make sure that output voltage of CVT fluid temperature sensor is within the range below.
4. Start engine and maintain the following conditions for at least 30 consecutive seconds.
With GST
Follow the procedure “With CONSULT-III”.
Is
“P1778 STEP MOTR/FNC” detected?
YES >> Go to TM-100, "Diagnosis Procedure".
NO >> Check intermittent incident. Refer to GI-35, "
Intermittent Incident".
Diagnosis ProcedureINFOID:0000000003849046
1.CHECK STEP MOTOR SYSTEM
Check step motor system. Refer to TM-97, "
Description".
Is the inspection result normal?
DTCItem
(CONSULT-III screen term)Malfunction is detected when... Possible cause
P1778 STEP MOTR/FNCThere is a big difference between the num-
ber of steps for the stepping motor and for
the actual gear ratio.Ste p m ot or
ATF TEMP SEN : 1.0 – 2.0 V
If it is out of range, drive the vehicle to decrease the voltage (warm up the fluid) or stop engine to increase the voltage
(cool down the fluid)
Start test from 0 km/h (0 MPH)
Constant acceleration : Keep 30 sec or more
VEHICLE SPEED : 10 km/h (6 MPH) or more
ACC PEDAL OPEN : More than 1.0/8
RANGE : “D” position
ENG SPEED : 450 rpm or more
TCM
TM-121
< ECU DIAGNOSIS >[CVT: RE0F09B]
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P Output Speed Sensor (Secondary Speed Sensor)
The shift pattern is changed in accordance with the throttle position when an unexpected signal is sent from
the output speed sensor (secondary speed sensor) to the TCM. The sport mode is inhibited, and the transaxle
is put in “D”.
Input Speed Sensor (Primary Speed Sensor)
The shift pattern is changed in accordance with the throttle position and secondary speed (vehicle speed)
when an unexpected signal is sent from the input speed sensor (primary speed sensor) to the TCM. The sport
mode is inhibited, and the transaxle is put in “D”.
PNP Switch
If an unexpected signal is sent from the PNP switch to the TCM, the transaxle is put in “D”.
CVT Fluid Temperature Sensor
If an unexpected signal is sent from the CVT fluid temperature sensor to the TCM, the gear ratio in use before
receiving the unexpected signal is maintained or the gear ratio is controlled to keep engine speed under 5,000
rpm.
Transmission Fluid Pressure Sensor A (Secondary Pressure Sensor)
If an unexpected signal is sent from the transmission fluid pressure sensor A (secondary pressure sensor) to
the TCM, the secondary pressure feedback control is stopped and the offset value obtained before the non-
standard condition occurs is used to control line pressure.
If transmission fluid pressure sensor A (secondary pressure sensor) error signal is inputted to the TCM, sec-
ondary pressure feedback control stops, but line pressure is controlled normally.
Pressure Control Solenoid A (Line Pressure Solenoid Valve)
If an unexpected signal is sent from the solenoid valve to the TCM, the pressure control solenoid A (line pres-
sure solenoid valve) is turned OFF to achieve the maximum fluid pressure.
Pressure Control Solenoid B (Secondary Pressure Solenoid Valve)
If an unexpected signal is sent from the solenoid valve to the TCM, the pressure control solenoid B (secondary
pressure solenoid valve) is turned OFF to achieve the maximum fluid pressure.
Torque Converter Clutch Solenoid Valve
If an unexpected signal is sent from the solenoid valve to the TCM, the torque converter clutch solenoid valve
is turned OFF to cancel the lock-up.
Ste p M oto r
If an unexpected signal is sent from the step motor to the TCM, the step motor coil phases “A” through “D” are
all turned OFF to hold the gear ratio used just before the non-standard condition occurred.
CVT Lock-up Select Solenoid Valve
If an unexpected signal is sent from the solenoid valve to the TCM, the CVT lock-up select solenoid valve is
turned OFF to cancel the lock-up.
TCM Power Supply (Memory Back-up)
Transaxle assembly is protected by limiting the engine torque when the memory back-up power supply (for
controlling) from the battery is not supplied to the TCM. Normal status is restored when turning the ignition
switch OFF to ON after the normal power supply.
DTC Inspection Priority ChartINFOID:0000000003849062
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC “U1000 CAN COMM CIRCUIT” is indicated with other DTCs, start from a diagnosis for “DTC
U1000 CAN COMMUNICATION LINE”. Refer to TM-41
.
DTC IndexINFOID:0000000003849063
NOTE:
Priority Detected items (DTC)
1 U1000 CAN communication line
2 Except above
SYSTEM SYMPTOM
TM-125
< SYMPTOM DIAGNOSIS >[CVT: RE0F09B]
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P6
Slips/Will
Not EngageDoes not lock-up.ON vehicle1. CVT fluid level and stateTM-142
2. Line pressure testTM-146
3. Engine speed signalTM-59
4. Primary speed sensorTM-52
5. Torque converter clutch solenoid valveTM-62
6. CAN communication lineTM-41
7. Stall testTM-144
8. Step motorTM-97
9. PNP switchTM-44
10. Lock-up select solenoid valveTM-94
11. CVT fluid temperature sensorTM-50
12. Secondary speed sensorTM-55
13. Secondary pressure sensorTM-74
OFF vehicle14. Torque converterTM-17215. Oil pump assembly
TM-168
16. Control valve
7Does not hold lock-up
condition.ON vehicle1. CVT fluid level and stateTM-142
2. Line pressure testTM-146
3. Engine speed signalTM-59
4. Primary speed sensorTM-52
5. Torque converter clutch solenoid valveTM-62
6. CAN communication lineTM-41
7. Stall testTM-144
8. Step motorTM-97
9. PNP switchTM-44
10. Lock-up select solenoid valveTM-94
11. CVT fluid temperature sensorTM-50
12. Secondary speed sensorTM-55
13. Secondary pressure sensorTM-74
OFF vehicle14. Torque converterTM-17215. Oil pump assembly
TM-168
16. Control valve No. Item Symptom Condition Diagnostic item Reference
TM-126
< SYMPTOM DIAGNOSIS >[CVT: RE0F09B]
SYSTEM SYMPTOM
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Slips/Will
Not EngageLock-up is not re-
leased.ON vehicle1. CVT fluid level and stateTM-142
2. Line pressure testTM-146
3. Engine speed signalTM-59
4. Primary speed sensorTM-52
5. Torque converter clutch solenoid valveTM-62
6. CAN communication lineTM-41
7. Stall testTM-144
OFF vehicle8. Torque converterTM-1729. Oil pump assembly
TM-168
10. Control valve
9With selector lever in
“D” position, accelera-
tion is extremely poor.ON vehicle1. CVT fluid level and stateTM-142
2. Line pressure testTM-146
3. Stall testTM-144
4. Accelerator pedal position sensorTM-88
5. CAN communication lineTM-41
6. PNP switchTM-44
7. CVT positionTM-152
8. Step motorTM-97
9. Primary speed sensorTM-52
10. Secondary speed sensorTM-55
11. Accelerator pedal position sensorTM-88
12. Primary pressure sensorTM-80
13. Secondary pressure sensorTM-74
14. CVT fluid temperature sensorTM-50
15. TCM power supply and groundTM-85
OFF vehicle16. Torque converterTM-17217. Oil pump assembly
TM-168
18. Forward clutch
19. Control valve No. Item Symptom Condition Diagnostic item Reference
SYSTEM SYMPTOM
TM-127
< SYMPTOM DIAGNOSIS >[CVT: RE0F09B]
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Slips/Will
Not EngageWith selector lever in
“R” position, accelera-
tion is extremely poor.ON vehicle1. CVT fluid level and stateTM-142
2. Line pressure testTM-146
3. Stall testTM-144
4. Accelerator pedal position sensorTM-88
5. CAN communication lineTM-41
6. PNP switchTM-44
7. CVT positionTM-152
8. Step motorTM-97
9. Primary speed sensorTM-52
10. Secondary speed sensorTM-55
11. Accelerator pedal position sensorTM-88
12. Primary pressure sensorTM-80
13. Secondary pressure sensorTM-74
14. CVT fluid temperature sensorTM-50
15. TCM power supply and groundTM-85
OFF vehicle16. Torque converterTM-17217. Oil pump assembly
TM-168
18. Reverse brake
19. Control valve
11 Slips at lock-up.ON vehicle1. CVT fluid level and stateTM-142
2. Line pressure testTM-146
3. Engine speed signalTM-59
4. Primary speed sensorTM-52
5. Torque converter clutch solenoid valveTM-62
6. CAN communication lineTM-41
7. Stall testTM-144
8. Step motorTM-97
9. PNP switchTM-44
10. Lock-up select solenoid valveTM-94
11. CVT fluid temperature sensorTM-50
12. Secondary speed sensorTM-55
13. Secondary pressure sensorTM-74
OFF vehicle14. Torque converterTM-17215. Oil pump assembly
TM-168
16. Control valve No. Item Symptom Condition Diagnostic item Reference
TM-130
< SYMPTOM DIAGNOSIS >[CVT: RE0F09B]
SYSTEM SYMPTOM
15
OthersWith selector lever in
“R” position, driving is
not possible.ON vehicle1. CVT fluid level and stateTM-142
2. Line pressure testTM-146
3. PNP switchTM-44
4. Stall testTM-144
5. CVT positionTM-152
6. Step motorTM-97
7. Primary speed sensorTM-52
8. Secondary speed sensorTM-55
9. Accelerator pedal position sensorTM-88
10. CVT fluid temperature sensorTM-50
11. Secondary pressure sensorTM-74
12. TCM power supply and groundTM-85
OFF vehicle13. Torque converterTM-172
14. Oil pump assembly
TM-168
15. Gear system
16. Reverse brake
17. Control valve
18. Parking components
16Judder occurs during
lock-up.ON vehicle1. CVT fluid level and stateTM-142
2. Engine speed signalTM-59
3. Primary speed sensorTM-52
4. Secondary speed sensorTM-55
5. Accelerator pedal position sensorTM-88
6. CAN communication lineTM-41
7. Torque converter clutch solenoid valveTM-62
OFF vehicle8. Torque converterTM-1729. Control valveTM-168
17Strange noise in “D”
position.ON vehicle1. CVT fluid level and stateTM-142
2. Engine speed signalTM-59
3. CAN communication lineTM-41
OFF vehicle4. Torque converterTM-172
5. Oil pump assembly
TM-168
6. Gear system
7. Forward clutch
8. Control valve
9. Bearing No. Item Symptom Condition Diagnostic item Reference
SYSTEM SYMPTOM
TM-131
< SYMPTOM DIAGNOSIS >[CVT: RE0F09B]
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OthersStrange noise in “R”
position.ON vehicle1. CVT fluid level and stateTM-142
2. Engine speed signalTM-59
3. CAN communication lineTM-41
OFF vehicle4. Torque converterTM-172
5. Oil pump assembly
TM-168
6. Gear system
7. Reverse brake
8. Control valve
19Strange noise in “N”
position.ON vehicle1. CVT fluid level and stateTM-142
2. Engine speed signalTM-59
3. CAN communication lineTM-41
OFF vehicle4. Torque converterTM-1725. Oil pump assembly
TM-168
6. Gear system
7. Control valve
20Vehicle does not de-
celerate by engine
brake.ON vehicle1. CVT fluid level and stateTM-142
2. CVT positionTM-152
3. Sport mode switchTM-108
4. CAN communication lineTM-41
5. Step motorTM-97
6. Primary speed sensorTM-52
7. Secondary speed sensorTM-55
8. Line pressure testTM-146
9. Engine speed signalTM-59
10. Accelerator pedal position sensorTM-88
OFF vehicle 11. Control valveTM-168
No. Item Symptom Condition Diagnostic item Reference
SYSTEM SYMPTOM
TM-133
< SYMPTOM DIAGNOSIS >[CVT: RE0F09B]
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OthersEngine stall.ON vehicle1. CVT fluid level and stateTM-142
2. Engine speed signalTM-59
3. Primary speed sensorTM-52
4. Torque converter clutch solenoid valveTM-62
5. CAN communication lineTM-41
6. Stall testTM-144
7. Secondary pressure sensorTM-74
OFF vehicle8. Torque converterTM-1729. Control valveTM-168
26Engine stalls when
selector lever is shift-
ed “N”→“D”or “R”.ON vehicle1. CVT fluid level and stateTM-142
2. Engine speed signalTM-59
3. Primary speed sensorTM-52
4. Torque converter clutch solenoid valveTM-62
5. CAN communication lineTM-41
6. Stall testTM-144
OFF vehicle7. Torque converterTM-1728. Control valveTM-168
27Engine speed does
not return to idle.ON vehicle1. CVT fluid level and stateTM-142
2. Accelerator pedal position sensorTM-88
3. Secondary speed sensorTM-55
4. CAN communication lineTM-41
OFF vehicle 5. Control valveTM-168
28 CVT does not shiftON vehicle1. CVT fluid level and stateTM-142
2. CVT positionTM-152
3. Line pressure testTM-146
4. Engine speed signalTM-59
5. Accelerator pedal position sensorTM-88
6. CAN communication lineTM-41
7. Primary speed sensorTM-52
8. Secondary speed sensorTM-55
9. Step motorTM-97
OFF vehicle10. Control valve
TM-16811. Oil pump assembly
29Engine does not start
in “N” or “P” position.ON vehicle1. Ignition switch and starterPG-55
, STR-6
2. CVT positionTM-152
3. PNP switchTM-44
No. Item Symptom Condition Diagnostic item Reference