Mitsubishi Galant 9G. Manual — part 305

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-6

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
1. Connect the scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System Select."
5. Choose "AUTO A/C" from the "BODY" tab.
6. Select "MITSUBISHI."
7. Select "Data List."
8. Choose an appropriate item and select the "OK" button.

HOW TO PERFORM ACTUATOR TEST

Required Special Tools:

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

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A (Vehicles with CAN

communication system)

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
1. Connect the scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System Select."
5. Choose "AUTO A/C" from the "BODY" tab.
6. Select "MITSUBISHI."
7. Choose "Actuator Test" from "AUTO A/C" screen.
8. Choose an appropriate item and select the "OK" button.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-7

HOW TO DIAGNOSE THE CAN BUS LINE

Required Special Tools:

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

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Select "CAN bus diagnosis" from the start-up screen.
4. When the vehicle information is displayed, confirm that it

matches the vehicle whose CAN bus lines will be
diagnosed.

• If they match, go to step 8.

• If not, go to step 5.

5. Select "view vehicle information" button.
6. When the vehicle information is displayed, confirm again

that it matches the vehicle which is diagnosed CAN bus line.

• If they match, go to step 8.

• If not, go to step 5.

7. Press the "OK" button.
8. When the options are displayed, choose the options (mark

the check) and then select "OK".

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-8

DIAGNOSTIC TROUBLE CODE CHART

M1554004900225

CAUTION

During diagnosis, a DTC code associated with
another system may be set when the ignition
switch is turned on with connector(s) discon-
nected. After completing the repair, confirm all
systems for DTC code(s). If DTC code(s) are set,
erase them all.

DIAGNOSTIC
TROUBLE CODE
NO.

DIAGNOSTIC ITEM

REFERENCE
PAGE

B1001

Interior temperature sensor system (short circuit)

P.55B-9

B1002

Interior temperature sensor system (open circuit)

P.55B-9

B1011

Ambient temperature sensor system (short circuit)

Refer to
GROUP 55A,
DIAGNOSTIC
TROUBLE
CODE
CHART

P.55A-

58

B1012

Ambient temperature sensor system (open circuit)

B1021

Air thermo sensor system (short circuit)

B1022

Air thermo sensor system (open circuit)

B1041

Air mixing damper control motor and potentiometer (potentiometer
system shorted to its power supply)

B1042

Air mixing damper control motor and potentiometer (potentiometer
system shorted to its ground or open circuit)

B1045

Air mixing damper control motor and potentiometer (activating
system failure)

B1061

Mode selection damper control motor and potentiometer
(potentiometer system shorted to its power supply)

B1062

Mode selection damper control motor and potentiometer
(potentiometer system shorted to its ground or open circuit)

B1065

Mode selection damper control motor and potentiometer (activating
system failure)

U1073

Bus off

U1100

Powertrain control module time-out (related to engine)

U1111

Multi-center display unit (middle grade type) time-out

U1120

Failure information on powertrain control module (related to engine)

AUTO A/C DIAGNOSIS

TSB Revision

AUTOMATIC AIR CONDITIONING

55B-9

DIAGNOSTIC TROUBLE CODE PROCEDURES

DTC B1001, B1002: Interior Temperature Sensor System

DTC SET CONDITION

• DTC B1001 is set if there is a short circuit in the

interior temperature sensor input circuit.

• DTC B1002 is set if there is a defective connector

connection, or if there is an open circuit in the
harness.

.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble

• The A/C-ECU, the interior air temperature sensor,

or connector(s) or wiring between the two may be
defective.

Past trouble

• If DTC B1001 or B1002 is stored as a past trou-

ble, carry out diagnosis with particular emphasis

on wiring and connector(s) between the A/C-ECU

and the interior air temperature sensor. If the con-

nectors and wiring are normal, and obviously the

ECU is the cause of the trouble, replace the ECU.

If in doubt, do not replace the ECU.

.

TROUBLESHOOTING HINT

• Malfunction of connector.

• Malfunction of the harness.

• Malfunction of the interior temperature sensor.

• Malfunction of the A/C-ECU.

A/C-ECU

JOINT
CONNECTOR (2)

INTERIOR
TEMPERATURE
SENSOR

Interior Temperature Sensor Circuit

AC305233

C-16 (B)

C-15 (B)

CONNECTORS: C-15, C-16

BE

AC305231CL

CONNECTOR: C-03, C-123

C-123

C-03