Mitsubishi Galant 9G. Manual — part 248

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-68

STEP 3. Using scan tool MB991958, check data list item 03:
air thermo sensor.

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) Ignition switch: ON
(3) Set scan tool MB991958 to the data reading mode for item

03: air thermo sensor.

• Check that the passenger room temperature matches

the displayed value on the scan tool while the engine is
cold.

NOTE: When this DTC is set and the system is fail-safe sta-
tus, the value of service data displays

−

6

°

C.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor within the specified range?

YES : Replace the A/C-ECU. Then go to Step 7.
NO : Go to Step 4.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-69

STEP 4. Check A/C-ECU connectors C-15, C-16 and air
thermo sensor connector C-126 for loose, corroded or
damaged terminals, or terminals pushed back in the
connector.
Q: Are A/C-ECU connectors C-15, C-16 and air thermo

sensor connector C-126 in good condition?
YES : Go to Step 5.
NO : Repair or replace the connector. Refer to GROUP

00E, Harness Connector Inspection

P.00E-2

. Then go

to Step 7.

AC305234

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

AG

AC305231

CONNECTOR: C-126

CB

HARNESS SIDE

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-70

STEP 5. Check the wiring harness between A/C-ECU
connector C-15 (terminal 20), C-16 (terminal 24) and air
thermo sensor connector C-126 (terminals 1 and 2).

AC305234

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

AG

AC305232

C-03

C-126

C-03

HARNESS SIDE

C-126

AP

CONNECTORS: C-03, C-126

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-71

NOTE: Also check joint connector C-03 for loose, corroded, or
damaged terminals, or terminals pushed back in the connector.
If joint connector C-03 is damaged, repair or replace the con-
nector as described in GROUP 00E, Harness Connector
Inspection

P.00E-2

.

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

(terminal 20), C-16 (terminal 23) and air thermo sensor
connector C-126 (terminals 1 and 2) in good condition?
YES : Go to Step 6.
NO : Repair the wiring harness. Then go to Step 7.

STEP 6. Check the air thermo sensor.
(1) Disconnect the air thermo sensor connector C-126.

(2) Measure the resistance between connector terminals 1 and

2 under at least two different temperatures. The resistance
values should generally match those in the graph.
NOTE: The temperature at the check should not exceed the
range in the graph.

Q: Is the air thermo sensor in good condition?

YES : Replace the A/C-ECU. Then go to Step 7.
NO : Replace the air thermo sensor. Then go to Step 7.

AC305231

CONNECTOR: C-126

CB

HARNESS SIDE

AC001043

RESISTANCE k

Ω

8

6

4

2

0

-10

0

10

20

30

40

TEMPERATURE ˚C(˚F)

AB

(14)

(32)

(50)

(86)

(104)

(68)