Mitsubishi Galant 9G. Manual — part 270

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-156

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.

STEP 5. Check A/C-ECU connector C-10 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is A/C-ECU connectors C-10 in good condition?

YES : Go to Step 6.
NO : Repair or replace the connector. Refer to GROUP

00E, Harness Connector Inspection

P.00E-2

. 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

AC305233AW

CONNECTOR: C-10

HARNESS SIDE

C-10 (B)

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-157

STEP 6. Check the wiring harness between A/C-ECU
connector C-10 (terminals 4, 1 and 3) and A/C pressure
sensor connector A-30 (terminals 2, 1 and 3).

NOTE: Also check intermediate connector C-29 for loose, cor-
roded, or damaged terminals, or terminals pushed back in the
connector. If intermediate connector C-29 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-10

(terminals 4, 1 and 3) and A/C pressure sensor
connector A-30 (terminals 2, 1 and 3) in good condition?
YES : Replace the A/C-ECU. Check that the air conditioning

works normally.

NO : Repair the wiring harness. Check that the air

conditioning works normally.

STEP 7. Check the refrigerant level.
Use the refrigerant recovery station to remove all of the refrig-
erant, and then calculate the amount of the refrigerant and
charge it.
Q: Is the refrigerant level correct?

YES : Replace the A/C-ECU.
NO : Correct the refrigerant level (Refer to On-vehicle

Service

P.55A-262

). Check that the air conditioning

works normally.

AC305233AW

CONNECTOR: C-10

HARNESS SIDE

C-10 (B)

AC305206

CONNECTOR: A-30

AY

HARNESS SIDE

A-30 (B)

AC305231AI

CONNECTOR: C-29

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-158

INSPECTION PROCEDURE 8: Defogger Function Does Not Operate.

IGNITION
SWITCH (IG2)

1

FUSIBLE
LINK

REAR
WINDOW
DEFOGGER
RELAY

CAPACITOR

REAR WINDOW
DEFOGGER

A/C-
ECU

Rear Window Defogger Circuit

JUNCTION
BLOCK

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-159

.

TECHNICAL DESCRIPTION (COMMENT)

If the defogger does not operate when the defogger
switch is turned on, the defogger relay system may
be defective.

.

TROUBLESHOOTING HINTS

• Malfunction of the A/C-ECU

• Malfunction of the defogger relay

• Damaged harness wires or connectors

DIAGNOSIS

Required Special Tool:

• MB991223: Test Harness Set

STEP 1. Check the A/C and outside/inside air selection
damper control motor operation.
Q: Do the A/C and outside/inside air selection damper

control motor work normally?
YES : Go to Step 2.
NO : Refer to Inspection procedure 10, "Malfunction of the

A/C-ECU power supply system

P.55A-170

."

AC305233

CONNECTOR: C-09

BS

C-09 (B)

AC305231CH

CONNECTOR: C-29

AC207120

C-216 (B)

CONNECTORS: C-201, C-204, C-211, C-215,
C-216

C-201

C-215

C-211

AZ

C-204

AC305268

CONNECTORS: D-08, D-11, D-13, D-14

D-08

D-11

D-13

D-14

AL