Mitsubishi Galant 9G. Manual - part 1598

MULTI-CENTER DISPLAY

TSB Revision

CHASSIS ELECTRICAL

54A-264

INSPECTION PROCEDURE 3: The A/C Display Shows "COMMUNICATION ERROR", and then can not 
Proceed to Next Screen. (Middle Grade Type)

POWERTRAIN
CONTROL MODULE

JOINT
CONNECTOR (3)

WITHOUT ELECTRONIC 
BRAKE-FORCE 
DISTRIBUTION (EBD) 
AND ANTI-LOCK 
BRAKING 
SYSTEM (ABS)

WITH ELECTRONIC 
BRAKE-FORCE 
DISTRIBUTION (EBD) 
AND ANTI-LOCK 
BRAKING 
SYSTEM (ABS)

WITH ELECTRONIC 
BRAKE-FORCE 
DISTRIBUTION (EBD) 
AND ANTI-LOCK 
BRAKING 
SYSTEM (ABS)

WITHOUT ELECTRONIC 
BRAKE-FORCE 
DISTRIBUTION (EBD) 
AND ANTI-LOCK 
BRAKING 
SYSTEM (ABS)

MULTI-CENTER 
DISPLAY UNIT

CPU

A/C-ECU

COMBINATION METER

ABS-ECU OR ABS/TCL-ECU

CAN-BUS Line Circuit

MULTI-CENTER DISPLAY

TSB Revision

CHASSIS ELECTRICAL

54A-265

.

CIRCUIT OPERATION

The multi-center display unit (middle grade type) 
receives information on current A/C operation condi-
tion from the A/C-ECU via CAN bus lines.

.

TECHNICAL DESCRIPTION (COMMENT)

The multi-center display unit (middle grade type) will 
show "COMMUNICATION ERROR" message if it 
has received abnormal data from the A/C-ECU via 
CAN communication for 60 seconds or more. Then 
the A/C operation screen, which is based on the last 
normal information, continues to be shown. If the 
communication returns to normal, "COMMUNICA-
TION ERROR" message will disappear and the A/C 
operation screen will return to normal.

.

TROUBLESHOOTING HINTS

• Malfunction of multi-center display unit (middle 

grade type)

• Malfunction of A/C-ECU

• The wiring harness or connectors may have 

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector.

DIAGNOSIS 

Required Special Tools:

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

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

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness A (Vehicles with CAN 

communication system)

AC305206

CONNECTOR: A-02

AO

A-02 (GR)

AC305216

B-19 (B)

CONNECTOR: B-19

AD

AC305231

C-02

C-29

C-101

DD

CONNECTORS: C-02, C-29, C-101

AC305233

CONNECTORS: C-05, C-15

CQ

C-05 (B)

C-15 (B)

MULTI-CENTER DISPLAY

TSB Revision

CHASSIS ELECTRICAL

54A-266

STEP 1. Using scan tool MB991958, diagnose the CAN bus 
line
Use scan tool MB991958 to diagnose the CAN bus lines.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to "ON" position.
(3) Diagnose the CAN bus line.
Q: Is the check result satisfactory?

YES : Go to Step 2.
NO :  Repair the CAN bus lines (Refer to GROUP 54C, 

Diagnosis-Can Bus Diagnostic Chart 

P.54C-14

). After 

diagnosing the CAN bus lines, go to Step 3.

STEP 2. Using scan tool MB991958, read A/C diagnostic 
trouble code.
Check if an A/C system DTC is set.
Q: Is the DTC set?

YES : Refer to GROUP 55A, Manual A/C Diagnosis 

− 

Diagnostic Trouble Code Chart <Low Type>

P.55A-10

  

or GROUP 55A, Diagnostic Trouble Code Chart 
<Middle Type>

P.55A-58

  or Auto A/C Diagnostic 

Trouble Code Chart 

P.55B-8

 and then go to Step 3    .

NO :  Replace multi-center display unit (middle grade type) 

and then go to Step 3.

STEP 3. Retest the system
Check if the A/C operation screen is displayed normally.
Q: Is the check result satisfactory?

YES : The procedure is complete.
NO :  Go to Step 1.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTI-CENTER DISPLAY

TSB Revision

CHASSIS ELECTRICAL

54A-267

INSPECTION PROCEDURE 4: The Ambient Air Temperature Display Shows "COM ERROR" or 
"

−−deg°C (−−°F)." (Middle Grade Type)

A/C-ECU

JOINT 
CONNECTOR (3)

JOINT 
CONNECTOR (2)

COMBINATION 
METER

AMBIENT AIR
TEMPERATURE 
SENSOR

CPU

MULTI-CENTER 
DISPLAY UNIT

ABS-ECU OR ABS/TCL-ECU

WITHOUT ELECTRONIC 
BRAKE-FORCE 
DISTRIBUTION (EBD) 
AND ANTI-LOCK 
BRAKING SYSTEM 
(ABS)

WITHOUT ELECTRONIC 
BRAKE-FORCE 
DISTRIBUTION (EBD) 
AND ANTI-LOCK 
BRAKING SYSTEM 
(ABS)

WITH ELECTRONIC 
BRAKE-FORCE 
DISTRIBUTION (EBD) 
AND ANTI-LOCK 
BRAKING SYSTEM 
(ABS)

WITH ELECTRONIC 
BRAKE-FORCE 
DISTRIBUTION (EBD) 
AND ANTI-LOCK 
BRAKING SYSTEM 
(ABS)

POWERTRAIN 
CONTROL 
MODULE

CAN-BUS Line and Ambient Air Temperature Sensor Circuit