Mitsubishi 380. Manual — part 181

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-20

STEP 7. Check the wiring harness between A/C-ECU
connector C-15 (terminals 20), C-16 (terminal 23) and
ambient air temperature sensor connector A-25 (terminals
1 and 2).

NOTE: Also check intermediate connector C-23 for loose, cor-
roded, or damaged terminals, or terminals pushed back in the
connector. If intermediate connector C-23 is damaged, repair or
replace the connector as described in GROUP 00E, Harness
Connector Inspection

P.00E-2

.

Q: Is the wiring harness between A/C-ECU connector C-15

(terminals 20), C-16(terminal 23) and ambient air
temperature sensor connector A-25 (terminals 1 and 2)
in good condition?
YES : Replace the A/C-ECU. Then go to Step 8.
NO : Repair the wiring harness. Then go to Step 8.

25DB076A

C-23

C-10

C-23

HARNESS SIDE

CONNECTORS: C-10,C-23

C-10 (B)

AC305210

A-25 (BR)

HARNESS SIDE

CONNECTOR: A-25

AP

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-21

STEP 8. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Connect diagnostic tool to the data link connector
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the check result satisfactory?

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

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-22

DTC B1021, B1022: Air Thermo Sensor System

.

DTC SET CONDITION

• DTC B1021 is set if there is a short circuit in the

air thermo sensor input circuit.

• DTC B1022 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 air thermo sensor, or connec-

tor(s) or wiring between the two may be defec-
tive.

Past trouble

• If DTC B1021 or B1022 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 air thermo sensor. If the connectors 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 air thermo sensor.

• Malfunction of the A/C-ECU.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

25DB070A

CONNECTORS: C-15, C-16

C-16 (B)

HARNESS SIDE

C-16

C-15

C-15 (B)

HARNESS SIDE

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

25DB079A

CONNECTOR: C-126

C-126

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-23

DIAGNOSIS

Required Special Tool:

• : Diagnostic 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)

STEP 1. Using diagnostic tool , diagnose the CAN bus line.
Use diagnostic tool to diagnose the CAN bus lines.
(1) Connect diagnostic tool 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. Repair the CAN bus lines

(Refer to GROUP 54C, Diagnosis-Can Bus
Diagnostic Chart

P.54C-405

). Then go to Step 7.

STEP 2. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to "ON" position.
(3) Check if the DTC is set.

Q: Is the check result satisfactory?

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 3.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827