Mitsubishi 380. Manual — part 398

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-132

STEP 14. Using diagnostic tool MB991958, check data list
item 34: Transmission Inhibitor Switch.

CAUTION

To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect diagnostic tool MB991958 to the data link

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Set diagnostic tool MB991958 to data reading mode.

• Item 34: Transmission Inhibitor Switch.

• Move the selector lever to "P," "R," "N," "D" and sport

mode positions and confirm that the selected trans-
mission ranges match the positions. (Sport mode is
indicated as "D" on the diagnostic tool MB991958).

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

Q: Is the switch operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to

Cope with Intermittent Malfunction

P.00-14

.

NO : Replace the A/T-ECU.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-133

(P0753): Low-Reverse Solenoid Valve System

.

CIRCUIT OPERATION

• The A/T control relay supplies battery positive

voltage to the solenoid valve assembly (terminals
9 and 10).

• The solenoid valve closes when energized (on),

and opens when not energized (off). The
A/T-ECU energizes the solenoid valve based on
input data from sensors such as the Throttle
Position Sensor, Transmission Inhibitor Switch,
Stoplight Switch, Input Shaft Speed Sensor, Out-
put Shaft Speed Sensor, and Transmission Fluid
Temperature Sensor.

• The A/T-ECU provides the ground to energize the

solenoid. The amount of time that the circuit is
grounded is displayed on diagnostic tool
MB991958 in percent.

• When the solenoid is energized or de-energized,

fluid passes through the valve body and
transmission passages to apply and release com-
ponents.

.

DTC SET CONDITIONS

Check Conditions

• Solenoid status: either solid ON or OFF.

• Shift status: in-gear.

• Voltage of battery: 10 volts or more.

Judgement Criteria

• Solenoid voltage: 3 volts or less. (0.3 second)

• If (P0753) is set consecutively four times, the

transmission is locked into 3rd gear as a fail-safe
measure, and the "N" range light flashes once
per second.

.

OBD-II DRIVE CYCLE PATTERN

Start the engine, and keep the vehicle stopped in "P"
range for 5 seconds.

.

AC306223

A-13 (GR)

AB

CONNECTOR: A-13

1

4

7

8

2 3

5

13 14

17

15

12

16

11

10

9

6

10DB098A

RELAY BOX

CONNECTOR: B-16X

2

1

3 4

FRONT OF
VEHICLE

16DB564A

COVER

AIR

CLEANER

A/T

CONTROL

UNIT

CONNECTORS: B-19, B-22

AC306322

CONNECTOR: B-108

B-108 (GR)

AC

TRANSMISSION
RANGE SWITCH

2

7

1

8

3

9

4

6

10

5

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-134

TROUBLESHOOTING HINTS (THE MOST
LIKELY CAUSES FOR THIS CODE TO BE
SET ARE:)

• Malfunction of the low-reverse solenoid valve

• Damaged harness or connector

• Malfunction of the A/T-ECU

Circuit drawings

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• Refer to component locations GROUP-

70

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. Using diagnostic tool MB991958, check actuator
test item 01: Low-Reverse Solenoid Valve.

CAUTION

To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
(1) Connect diagnostic tool MB991958 to the data link

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Set diagnostic tool MB991958 to the actuator test mode.

• Item 01: Low-Reverse Solenoid Valve.

• An audible clicking or buzzing should be heard when

the low-reverse solenoid valve is energized.

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

Q: Is the solenoid valve operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to

Cope with Intermittent Malfunctions

P.00-14

.

NO : Go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTOMATIC TRANSMISSION DIAGNOSIS

AUTOMATIC TRANSMISSION

23A-135

STEP 2. Using diagnostic tool MB991958, read the A/T
diagnostic trouble code.
(1) Connect diagnostic tool MB991958 to the data link

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Check for A/T diagnostic trouble code.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is (P1751) set? (P1751 may be set along with multiple

DTCs).
YES : Refer to

P.23A-207

P1751: A/T Control Relay

System.

NO : Go to Step 3.

STEP 3. Using diagnostic tool MB991958, read the A/T
diagnostic trouble code.
(1) Connect diagnostic tool MB991958 to the data link

connector.

(2) Turn the ignition switch to the "ON" position.
(3) Check for A/T diagnostic trouble code.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is (P0743) set?

YES : Go to Step 8.
NO : Go to Step 4.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827