Mitsubishi Space Star. Manual - part 113

AUTOMATIC TRANSMISSION – 

Troubleshooting <A/T>

23-19

INSPECTION CHART FOR TROUBLE SYMPTOMS

Trouble symptom

Inspection
procedure No.

Reference
page

Communication with MUT-

II

 is not possible

1

23-20

Driving impossible

Starting impossible

2

23-20

Does not move forward

3

23-21

Does not reverse

4

23-22

Does not move (forward or reverse)

5

23-22

Malfunction when starting

Engine stalling during shifting

6

23-23

Shocks when changing from N to D and large time lag

7

23-23

Shocks when changing from N to R and large time lag

8

23-24

Shocks when changing from N to D, N to R and large
time lag

9

23-25

Malfunction when shifting

Shocks and running up

10

23-25

Displaced shifting points

All points

11

23-26

Some points

12

23-27

Does not shift

No diagnosis codes

13

23-27

Malfunction while driving

Poor acceleration

14

23-28

Vibration

15

23-28

Inhibitor switch system

16

23-29

Shift switch assembly system

17

23-29

Dual pressure switch system

18

23-30

Vehicle speed sensor system

19

23-31

AUTOMATIC TRANSMISSION – 

Troubleshooting <A/T>

23-20

INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS

INSPECTION PROCEDURE 1

Communication with MUT-

II

 is not possible

Probable cause

If communication with the MUT-

II

 is not possible, the cause is probably a defective

diagnosis line or the engine-A/T-ECU is not functioning.



Malfunction of diagnosis line



Malfunction of connector



Malfunction of the engine-A/T-ECU

Is communication with other systems
possible using the MUT-

II

?

NO

Check the diagnosis line with MUT-

II

,

and repair if necessary.

YES

Check the continuity and voltage of the
engine-A/T-ECU connector.



Disconnect the connector, and
measure at the harness side.
B-85



Voltage between terminal No.41, 47
and earth
(Ignition switch: ON)
OK: System voltage



Continuity between B-86 terminals
No.76, 88, 97, B-85 terminals
No.48, 42 and earth

NG

Check the following connectors:
A-23, B-26, B-85, B-86

NG

Repair

OK

Harness check



Between ignition switch and
engine-A/T-ECU



Between earth and engine-
A/T-ECU

NG

Repair

OK

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

OK

Check the following connectors:
B-35, B-60X, B-61X, B-09, B-19,
B-86

NG

Repair

OK

Harness check



Between diagnosis connector and
engine-A/T-ECU

NG

Repair

OK

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

INSPECTION PROCEDURE 2

Starting impossible

Probable cause

Starting is not possible when the selector lever is in P or N range.In such cases,
the cause is probably a defective engine system, torque converter or oil pump.



Malfunction of the engine system



Malfunction of the torque converter



Malfunction of the oil pump



: Refer to the Transmission Workshop Manual.

Check the engine system.



Control system, ignition system, fuel system, main engine
system

NG

Repair, replace

OK

Torque converter check



Check for incorrect installation (inserted at an angle, etc.) and
for damaged splines.

NG

Repair if possible. If the splines are damaged and repairs are
not possible, replace the torque converter assembly.

OK

Repalce the oil pump assembly. 



 

(The oil pump cannot be disassembled.)

Inspection Procedure 16: Inhibitor switch system check (Refer
to P.23–29)

Transmission control cable assembly check

OK

NG

Repair, replace

OK

NG

Repair

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

AUTOMATIC TRANSMISSION – 

Troubleshooting <A/T>

23-21

INSPECTION PROCEDURE 3

Does not move (forward)

Probable cause

If the vehicle does not move forward when the selector lever is shifted from N to
D, Sports mode 1st or 2nd range while the engine is idling, the cause is probably
abnormal line pressure or a malfunction of the underdrive clutch or valve body.



Abnormal line pressure



Malfunction of the underdrive solenoid valve



Malfunction of the underdrive clutch



Malfunction of the valve body



: Refer to the Transmission Workshop Manual.

MUT-

II

 Actuator test



No. 2 Underdrive solenoid valve
OK: Sound of operation can be heard.

NG

Replace the solenoid valve. 



OK

Hydraulic pressure test (Refer to P.23-51.)



Measure the hydraulic pressure for each element when in
L range.
Standard value: Refer to P.23-52.

NG

Valve body disassembly, cleaning and reassembly 





Pay particular attention to loosening of bolts, and to damage
and slippage of O-rings, valves and valve bodies.



If the damage cannot be repaired, replace the valve body
assembly.

OK

Underdrive clutch system check 





Remove the transmission assembly, valve body cover and
valve body.



Pistons should operate and pressure should be maintained
when air is blown through the underdrive clutch oil hole in
the transmission case.

OK

Underdrive clutch check 





Check for burning of the facing, defective piston seal rings
and interference at the retainer.

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

OK

AUTOMATIC TRANSMISSION – 

Troubleshooting <A/T>

AUTOMATIC TRANSMISSION – 

Troubleshooting <A/T>

23-22

INSPECTION PROCEDURE 4

Does not reverse

Probable cause

If the vehicle does not reverse when the selector lever is shifted from N to R range
while the engine is idling, the cause is probably abnormal pressure in the reverse
clutch or low and reverse brake or a malfunction of the reverse clutch, low and
reverse brake or valve body.



Abnormal reverse clutch pressure



Abnormal low and reverse brake pressure



Malfunction of the low & reverse solenoid valve



Malfunction of the reverse clutch



Malfunction of the low and reverse brake



Malfunction of the valve body

NG



: Refer to the Transmission Workshop Manual.

MUT-

II

 Actuator test



No. 1 Low & reverse solenoid valve
OK: Sound of operation can be heard.

NG

Replace the low and reverse solenoid valve. 



OK

Hydraulic pressure check (Refer to P.23-51.)



Measure the reverse clutch pressure in R range.
Standard value: Refer to P.23-52.

NG

OK

Hydraulic pressure check (Refer to P.23-51.)



Measure the low & reverse brake pressure in R range.
Standard value: Refer to P.23-52.

NG

OK

Reverse clutch system and low and reverse brake system check





Remove the transmission assembly, valve body cover and
valve body.



Pistons should operate and pressure should be maintained
when air is blown through the reverse clutch oil hole and the
low reverse brake oil hole in the transmission case.

OK

NG

Reverse clutch and low and reverse brake check 





Check for burning of the facing, defective piston seal rings
and interference at the retainer.

Valve body disassembly, cleaning and reassembly 





Pay particular attention to loosening of bolts, and to damage
and slippage of O-rings, valves and valve bodies.



If the damage cannot be repaired, replace the valve body
assembly.

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

INSPECTION PROCEDURE 5

Does not move (forward or reverse)

Probable cause

If the vehicle does not move forward or reverse when the selector lever is shifted
to any position while the engine is idling, the cause is probably  abnormal line pressure,
or a malfunction of the power train, oil pump or valve body.



Abnormal line pressure



Malfunction of power train



Malfunction of the oil pump



Malfunction of the valve body



: Refer to the Transmission Workshop Manual.

Hydraulic pressure check (Refer to P.23-51.)



Measure the hydraulic pressure for each element when moving
forward and back.
Standard value: Refer to P.23-52.

OK

Power train check 





Disassemble the transmission, check the condition of the
planetary carrier, output shaft and differential, etc.

NG

Replace the oil pump assembly. 



 

(The oil pump cannot be disassembled.)

Valve body disassembly, cleaning and reassembly 





Pay particular attention to loosening of bolts, and to damage
and slippage of O-rings, valves and valve bodies.



If the damage cannot be repaired, replace the valve body
assembly.

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

NG