Mitsubishi 380. Manual - part 202

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-104

INSPECTION PROCEDURE 7: The A/C Indicator Flashes.

.

TECHNICAL DESCRIPTION (COMMENT)

If the A/C indicator flashes, inadequate refrigerant 
quantity, the ambient air temperature sensor circuit 
or the A/C pressure sensor circuit is suspected.

.

TROUBLESHOOTING HINTS

• Malfunction of the A/C pressure sensor

• Malfunction of the ambient air temperature sen-

sor

• Malfunction of the A/C-ECU

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

DIAGNOSIS

Required Special Tools:

• MB991223: Test Harness Set

•  : 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)

STEP 1. Using scan tool , read the diagnostic trouble code.
Check if an A/C-ECU DTC is set.
(1) Connect scan 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 : Go to Step 2.
NO :  Refer to DIAGNOSTIC TROUBLE CODE CHART 

P.55-9

.

AC305206

A-30 (B)

AZ

CONNECTOR: A-30

25DB068A

C-16 (B)

C-15 (B)

CONNECTORS: C-15, C-16

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-105

STEP 2. Using scan tool , check data list item 61: A/C 
pressure sensor.

CAUTION

To prevent damage to scan tool , always turn the ignition 
switch to the "LOCK" (OFF) position before connecting or 
disconnecting scan tool .
(1) Connect scan tool  to the data link connector.
(2) Assemble a manifold gauge onto the high pressure service 

valve.

(3) Turn ON the engine and then turn ON the air conditioner 

switch.

(4) Set scan tool  to the data reading mode for item 61: A/C 

pressure sensor.

• Check that the refrigerant pressure matches the dis-

played value on the scan tool.

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

Q: Is the sensor within the specified range?

YES : Go to Step 7.
NO :  Go to Step 3.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-106

STEP 3. Check A/C pressure sensor connector A-30 for 
loose, corroded or damaged terminals, or terminals 
pushed back in the connector.
Q: Is A/C pressure sensor connector A-30 in good 

condition?
YES : Go to Step 4.
NO :  Repair or replace the connector. Refer to GROUP 

00E, Harness Connector Inspection 

P.00E-2

. Check 

that the air conditioning works normally. 

AC305206

CONNECTOR: A-30

AY

HARNESS SIDE

A-30 (B)

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

AUTO A/C DIAGNOSIS

HEATER, AIR CONDITIONING AND VENTILATION

55-107

STEP 4. Check the A/C pressure sensor.
(1) Assemble a gauge manifold on the high pressure service 

valve.

(2) Disconnect the A/C pressure sensor connector and connect 

special tool test harness MB991658 as shown in the 
illustration.

(3) Turn ON the engine and then turn ON the air conditioner 

switch.

(4) At this time, check to see that the voltage of A/C pressure 

sensor terminal No. 2 reflects the specifications of the 
figure.

NOTE: The allowance shall be defined as 

±5%.

Q: Is the A/C pressure sensor in good condition?

YES : Go to Step 5.
NO :  Replace the A/C pressure sensor. Check that the air 

conditioning works normally. 

AC305034

A/C PRESSURE SENSOR

AD

AC307368

A/C 
PRESSURE 
SENSOR 
SIDE

MB991658

AB

HARNESS SIDE

AC208297AB

REFRIGERANT PRESSURE (MPa)

OUTPUT VOLTAGE 

(V)

0

1

2

3

5
4

1

2

3