Mitsubishi 380. Manual - part 395

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-120

DIAGNOSIS

Required Special Tool:

• MB991958: Diagnostic Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main harness A

STEP 1. Check the transmission inhibitor switch.
Measure the resistance between the terminals for each trans-
mission range as indicated in the table below.

Q: Does the resistance measure less than 2 ohms for each 

selector position?
YES : Go to Step 2.
NO :  Replace the transmission inhibitor switch. Refer to 

GROUP 23B, Transmission 

23B-13

.

TRANSMISSION 
RANGE

TERMINAL CONNECTION OF 
TESTER

SPECIFIED CONDITION

P

3 

− 8, 9 − 10

Less than 2 ohms.

R

7 

− 8

N

4 

− 8, 9 − 10

D

1 

− 8

AC305881

AC305532

AC305679

<F4A4B>

<F4A5A>

AC

TRANSMISSION
RANGE SWITCH

TRANSMISSION
RANGE SWITCH

AC210182AC

P

R

N

D

<F4A5A>

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-121

STEP 2. Check transmission inhibitor switch connector 
B-110 for loose, corroded or damaged terminals, or 
terminals pushed back in the connector.
Q: Are the connector and terminals in good condition?

YES : Go to Step 3.
NO :  Repair or replace the damaged components. Refer to 

GROUP 00E, Harness Connector Inspection 

P.00E-2

.

STEP 3. Check A/T-ECU connector B-22 for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Are the connector and terminals in good condition?

YES : Go to Step 4.
NO :  Repair or replace the damaged components. Refer to 

GROUP 00E, Harness Connector Inspection 

P.00E-2

.

AC210068

CONNECTOR: B-110

B-110 (B)

AE

TRANSMISSION
RANGE SWITCH

1

7

2

8

3

5

9

4

10

6

16DB564A

COVER

AIR

CLEANER

A/T

CONTROL

UNIT

CONNECTORS:  B-19, B-22

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-122

STEP 4. Measure the transmission inhibitor switch output 
voltage at A/T-ECU connector B-22 by using check 
harness special tool MB992045. ("P" position)
(1) Disconnect all the connectors from the A/T-ECU.

(2) Connect special tool MB992045 (check harness) between 

the A/T-ECU and the body-side harness connector.

(3) Turn the ignition switch to the "ON" position.

16DB564A

COVER

AIR

CLEANER

A/T

CONTROL

UNIT

CONNECTORS:  B-19, B-22

10DB161A

A/T-ECU CHECK HARNESS
    MB992045

A/T-ECU

A/T-ECU CHECK 
HARNESS
CONNECTORS

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-123

(4) Measure the voltage between terminal 25 and ground.

• When transmission range is "P," voltage should equal 

battery positive voltage.

• When transmission range is "R," voltage should mea-

sure 0.5 volt or less.

• When transmission range is "N," voltage should mea-

sure 0.5 volt or less.

• When transmission range is "D," voltage should mea-

sure 0.5 volt or less.

• When transmission range is sport mode, voltage should 

measure 0.5 volt or less.

Q: Is the measured voltage within the specified range?

YES : Go to Step 6.
NO :  Turn the ignition switch to the "LOCK" (OFF) position. 

Go to Step 5.

STEP 5. Check harness for damage between A/T-ECU 
connector B-22 terminal 25 and transmission inhibitor 
switch connector B-110 terminal 3.
Q: Is the harness wire in good condition?

YES : Go to Step 14.
NO :  Repair or replace the harness wire.

10DB094A

B-22 HARNESS 

CONNECTOR:

16DB564A

COVER

AIR

CLEANER

A/T

CONTROL

UNIT

CONNECTORS:  B-19, B-22

AC210068

CONNECTOR: B-110

B-110 (B)

AE

TRANSMISSION
RANGE SWITCH

1

7

2

8

3

5

9

4

10

6