Mitsubishi Space Star. Manual — part 115

AUTOMATIC TRANSMISSION –

Troubleshooting <A/T>

23-27

INSPECTION PROCEDURE 12

Some points (Displaced shifting points)

Probable cause

If some of the shift points are displaced while driving, the cause is probably a
malfunction of the valve body, or it is related to control and is not an abnormality.

Malfunction of the valve body

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

: Refer to the Transmission Workshop Manual.

INVECS-

II

CANCEL COMMAND

Use the MUT-

II

to stop the

INVECS-

II

function.

Does standard shifting occur normally?

NO

Does the problem occur only when the
automatic transmission fluid
temperature is –29

C or lower or 125

C

or higher?

NO

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.

YES

It is related to control and is not an
abnormality.

YES

INSPECTION PROCEDURE 13

No diagnosis codes (Does not shift)

Probable cause

If shifting does not occur while driving and no diagnosis codes are output, the cause
is probably a malfunction of the inhibitor switch, or engine-A/T-ECU.

Malfunction of the inhibitor switch

Malfunction of the shift switchassembly

Malfunction of the engine-A/T-ECU

INSPECTION PROCEDURE 17 - Shift
switch assembly system check (Refer
to P.23-29.)

Replace the engine-A/T-ECU.

NG

OK

YES

NO

Power supply circuit check

Pay particular attention to open
circuits in the harnesses, poor
connector connections and open
circuits in fuses.

If there is a blown fuse, investigate
why a short-circuis has occurred
and then replace the fuse.

Does the transmission remain in 3rd
gear with selector lever in position D?

NO

MUT-

II

Data list

No. 61 Inhibitor switch
OK: Engine-A/T-ECU input signal

and selector lever position
should match.

NG

Inhibitor switch check

INSPECTION PROCEDURE 16 -
Inhibitor switch system check.
(Refer to P.23-29.)

Is backup power being supplied to the
engine-A/T-ECU?

YES

Is power being supplied to the en-
gine-A/T-ECU?

YES

MUT-

II

Data list

No. 67 Select switch

No. 68 Upshift switch

No. 69 Downshift switch
OK: Engine-A/T-ECU input signal

and selector lever operation
should match.

YES

OK

AUTOMATIC TRANSMISSION –

Troubleshooting <A/T>

23-28

INSPECTION PROCEDURE 14

Poor acceleration

Probable cause

If acceleration is poor even if downshifting occurs while driving, the cause is probably
a malfunction of the engine system or of a brake or clutch.

Malfunction of the engine system

Malfunction of the brake or clutch

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

: Refer to the Transmission Workshop Manual.

Engine system check

Check the control system, ignition system, fuel system and
main system.

NG

Replace, repair

OK

Brake or clutch check

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

INSPECTION PROCEDURE 15

Vibration

Probable cause

If vibration occurs when driving at constant speed or when accelerating and
deceleration in top range, the cause is probably abnormal damper clutch pressure
or a malfunction of the engine system, damper clutch control solenoid valve, torque
converter or valve body.

Abnormal damper clutch pressure

Malfunction of the engine system

Malfunction of the damper clutch control solenoid
valve

Malfunction of the torque converter

Malfunction of the valve body

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

: Refer to the Transmission Workshop Manual.

MUT-

II

Actuator test

No. 6 Damper clutch control solenoid valve
OK: Sound of operation can be heard.

NG

Replace the damper clutch control solenoid valve.

OK

Does the problem occur even when the oil temperature sensor
connector is disconnected?

YES

Engine system check

Check the control system, ignition system, fuel system and
main system.

NO

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

Measure the damper clutch pressure.
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

Replace the torque converter assembly.

AUTOMATIC TRANSMISSION –

Troubleshooting <A/T>

23-29

INSPECTION PROCEDURE 16

Inhibitor switch system

Probable cause

The cause is probably a malfunction of the inhibitor switch circuit, ignition switch
circuit or a defective engine-A/T-ECU.

Malfunction of the inhibitor switch

Malfunction of the ignition switch

Malfunction of connector

Malfunction of the engine-A/T-ECU

Inhibitor switch check
(Refer to P.23-45.)

NG

Replace

OK

Check the voltage of the inhibitor switch
connector A-99.

Disconnect the connector and
measure at the harness side.

Voltage between terminal No. 8 and
earth
OK: System voltage

NG

Check the following connectors:
B-78, B-75, A-23

NG

Repair

OK

Harness check

Between inhibitor switch and
ignition switch

NG

Repair

OK

Check the trouble symptoms.

NG

Ignition switch check
(Refer to GROUP54 – Ignition Switch.)

OK

Check the following connectors:
A-99, B-87

NG

Repair

OK

Harness check

Between inhibitor switch and
engine-A/T-ECU connector

NG

Repair

OK

Check the trouble symptoms.

NG

Replace the engine-A/T-ECU.

INSPECTION PROCEDURE 17

Shift switch assembly system

Probable cause

The cause is probably a malfunction of the inhibitor switch circuit, shift switch assembly
circuit or a engine-A/T-ECU.

Malfunction of the inhibitor switch

Malfunction of the shift switch assembly

Malfunction of connector

Malfunction of the engine-A/T-ECU

Inhibitor switch check (Refer to P23-45.)

OK

NG

Replace

OK

OK

OK

INSPECTION PROCEDURE 16 - Inhibitor switch system
check (Refer to P.23-29.)

Shift switch assembly check (Refer to P23-65.)

Check the following connectors: B-91

Check the trouble symptoms.

Harness check

Between shift switch assembly and engine-A/T-ECU

Repair

Repair

Replace the engine-A/T-ECU.

NG

NG

NG

NG

AUTOMATIC TRANSMISSION –

Troubleshooting <A/T>

23-30

INSPECTION PROCEDURE 18

Dual pressure switch system

Probable cause

The cause is probably a defective dual pressure switch circuit or a defective
engine-A/T-ECU.

Malfunction of the dual pressure switch

Malfunction of connector

Malfunction of A/C system

Malfunction of the engine-A/T-ECU

Dual pressure switch check (Refer
to GROUP 55 – On-vehicle
service.)

NG

Replace

OK

Check the voltage of the engine-
A/T-ECU connector B-86.

Disconnect the connector and
check at the harness side.

Ignition switch: ON

A/C switch: ON

Voltage between terminal No. 83
and earth
OK: System voltage

OK

Check the following connectors:
A-33, A-23, B-86

NG

Repair

OK

Check the trouble symptoms.

NG

NG

Check the A/C system. (Refer to
GROUP 55 – Troubleshooting.)

Repair

OK

Replace the engine-A/T-ECU.

NG

A/C system check (Refer to GROUP
55 – Troubleshooting.)