Mitsubishi Galant. Manual — part 387

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-15

1. Connect the scan tool MB991502 to the data link connector.

2. Turn the ignition switch to "ON" position.

3. Record the diagnostic trouble codes for A/T.

4. Refer to the Diagnostic Trouble Code Chart.

5. Turn the ignition switch to "LOCK" (OFF) and then back to

"ON" again.

6. Erase the diagnostic trouble code by selecting DTC erase

from SPECIAL MENU screen, using scan tool.

7. Check for diagnostic trouble codes. Confirm the scan tool

displays "normal."

8. Turn the ignition switch to "LOCK" (OFF) position.

9. Disconnect the scan tool.

INSPECTION USING SCAN TOOL, ROAD TEST
AND DATA LIST

Required Special Tool:
MB991502: Scan Tool (MUT-II)

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.
1. Connect the scan tool MB991502 to data link connector.

2. Turn the ignition switch to "ON" position.

3. Carry out inspection by means of the Road Test or Data List

function. If there is an abnormality, check and repair the
chassis harnesses and components. Refer to

P.23A-17

,

Road Test. Refer to

P.23A-259

, Data List Reference Table.

4. Re-check using scan tool and check that the abnormal input

and output have returned to normal because of the repairs.

5. Erase the diagnostic trouble code(s).

6. Turn the ignition switch to "LOCK" (OFF) position.

7. Disconnect the scan tool from the data link connector.

8. Start the engine again and do a test drive to confirm that the

problem is eliminated.

FAIL-SAFE/BACKUP FUNCTION

M1231008300052

When malfunctions of the main sensors or actuators
are detected by the PCM, the transaxle is controlled
by pre-set control logic to maintain safe conditions
for driving.

AC003081AC

MB991502

DATA LINK
CONNECTOR

AC003081AC

MB991502

DATA LINK
CONNECTOR

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-16

MALFUNCTIONING
ITEM

JUDGEMENT
CONDITION

CONTROL CONTENTS DURING MALFUNCTION

Input shaft speed sensor No output pulse from the

input shaft speed sensor is
detected for one second or
more when the vehicle
speed is 30 km/h (19 mph)
or more.

The diagnostic trouble code is displayed when the
judgement condition occurs once. When the judge-
ment condition is met four times, the transaxle holds
3rd gear or 2nd gear depending on speed as a fail-
safe.

Output shaft speed sen-
sor

Output from the output
shaft speed sensor is con-
tinuously 50 % or less of
the output from the vehicle
speed sensor one second
or more when the vehicle
speed is 30 km/h (19 mph)
or more.

The diagnostic trouble code is displayed when the
judgement condition occurs once. When the judge-
ment condition is met four times, the transaxle holds
3rd gear or 2nd gear depending on speed as a fail-
safe.

Low-reverse solenoid
valve

Solenoid valve resistance
is below 2.7 W for 0.32
seconds.

When the judgement condition is met four times, the
A/T control relay is turned off.

Underdrive solenoid
valve

Second solenoid valve

Overdrive solenoid valve

Torque converter clutch
solenoid valve

Incomplete
shifting

1st

Gear ratio value which is
sent from the output shaft
speed sensor is not identi-
cal to the output from the
input shaft speed sensor
for one second after shift-
ing finished.

The diagnostic trouble code is displayed and the
judgement condition occurs once. When the judge-
ment condition is met four times, the A/T control re-
lay is turned off.

2nd

3rd

4th

Reverse

A/T control relay

A/T control relay voltage is
less than seven volts for
0.1 second after the igni-
tion switch is turned "ON."

Switch the A/T control relay off.

Abnormality in the PCM

Abnormality has occurred
in the PCM.

Switch the A/T control relay off.

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-17

ROAD TEST

M1231007800054

Check by the following procedures

STEP CONDITION

BEFORE TEST/
OPERATION

TEST/OPERATION

STANDARD

INSPECTI
ON ITEM

DTC

INSPECTION
PROCEDURE
PAGE

1

Ignition switch:
(LOCK) OFF

Ignition switch
(1) ON

Data list No. 54

(1) Control

Relay Voltage
[V]

A/T Control
relay
output
voltage

54

A/T Control
relay system
(

P.23A-208

.)

2

Ignition switch:
ON
Engine: Stopped
Selector lever
position: P

Selector lever position
(1) P, (2) R, (3) N, (4) D,
(5) 3, (6) 2, (7) L

Data list No. 61
(1) P, (2) R, (3)
N, (4) D, (5) 3,
(6) 2, (7) L

Park/
Neutral
position
switch

27,
28

Park/Neutral
position switch
system (

P.23A-

124

,

P.23A-

143

.)

Accelerator pedal
(1)Fully closed
(2)Depressed
(3)Fully open

Data list No. 11
(1)535

−

735 mV

(2)Gradually
rises from (1)
(3)4,500

−

5,500

mV

TPS

11,
12,
14

TPS system
(

P.23A-39

,

P.23A-48

,

P.23A-56

.)

Brake pedal
(1)Depressed
(2)Released

Data list No. 26
(1)ON
(2)OFF

Stoplight
switch

26

Stoplight
switch system
(

P.23A-117

.)

3

Ignition switch:
ST
Engine: Stopped

Starting test with
lever in P or N range

Starting should
be possible

Starting

-

Vehicles does
not move
(

P.23A-216

.)

4

Warming up

Drive for 15 minutes or
more so that the A/T fluid
temperature becomes 70

−

80

°

C. (158

−

176

°

F)

Data list No. 15
Gradually rises
to 70

−

80

°

C

(158

−

176

°

F)

A/T fluid
temperatur
e sensor

15,
16

A/T fluid
temperature
sensor system
(

P.23A-66

,

P.23A-73

.)

5

Engine: Idling
Selector lever
position: N

Brake pedal (Retest)
(1)Depressed
(2)Released

Data list No. 26
(1)ON
(2)OFF

Stoplight
switch

26

Stoplight
switch system
(

P.23A-117

.)

A/C switch
(1)ON
(2)OFF

Data list No. 65
(1)ON
(2)OFF

Dual
pressure
switch

-

Vehicle shifts
differently with
A/C engaged
(

P.23A-247

.)

Accelerator pedal
(1)Fully closed
(2)Depressed

Data list No. 21
(1)Engine
tachometer and
the MUT-II
shows the same
engine speed
(2)Gradually
rises from (1)

Crankshaft
position
sensor

21

Crankshaft
position sensor
system (

P.23A-

78

.)

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-18

5

Engine: Idling
Selector lever
position: N

Selector lever position
(1)N

→

D

(2)N

→

R

Should be no
abnormal shift
shocks
Time delay when
engaging should
be within 2
seconds

Malfunction
when
starting

-

Engine stalls
when moving
selector lever
from N to D or
N to R (

P.23A-

224

.)

-

Shift shocks
when shifting
from N to D
and long delay
(

P.23A-225

.)

-

Shift shocks
when shifting
from N to R
and long delay
(

P.23A-228

.)

-

Shift shocks
when shifting
from N to D, N
to R and long
delay (

P.23A-

231

.)

Does not
move

-

Does not move
forward
(

P.23A-218

.)

-

Does not move
backward
(

P.23A-220

.)

-

Does not move
(forward or
backward)
(

P.23A-223

.)

STEP CONDITION

BEFORE TEST/
OPERATION

TEST/OPERATION

STANDARD

INSPECTI
ON ITEM

DTC

INSPECTION
PROCEDURE
PAGE