Mitsubishi Galant (2004+). Manual - part 718

 

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Mitsubishi Galant (2004+). Manual - part 718

 

 

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-11

DIAGNOSTIC TROUBLE CODE PROCEDURES <LOW TYPE>

DTC B1011, B1012: Ambient Air Temperature Sensor System

CAUTION

If DTC B1011 or B1012 has been set, multi-dis-
play related DTC U1130 is also set. After B1011 or 
B1012 has been diagnosed, don't forget to erase 
DTC U1130.

AMBIENT AIR
TEMPERATURE
SENSOR

JOINT
CONNECTOR (2)

A/C-ECU

Ambient Temperature Sensor Circuit

AC305210

A-25 (BR)

AQ

CONNECTOR: A-25

AC305231AZ

CONNECTOR: C-03

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-12

.

DTC SET CONDITION

• DTC B1011 is set if there is a short circuit in the 

ambient air temperature sensor input circuit.

• DTC B1012 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 ambient air temperature sen-

sor, or connector(s) or wiring between the two 
may be defective.

Past trouble

• If DTC B1011 or B1012 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 ambient air temperature 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 ambient air temperature sen-

sor.

• Malfunction of the A/C-ECU.

DIAGNOSIS

Required Special Tool:

•  MB991958: 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)

AC305233AX

CONNECTORS: C-10, C-23

C-10 (B)

C-23

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-13

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. Repair the CAN bus lines 

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

P.54C-621

). Then go to Step 8.

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 

Use Troubleshooting/Inspection Service Points 

P.00-6

.

NO :  Go to Step 3. 

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-14

STEP 3. Using scan tool MB991958, check data list item 02: 
Ambient air temperature 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) Start the engine.
(3) Set scan tool MB991958 to the data reading mode for item 

02: Ambient air temperature sensor.

• Check that the ambient temperature matches the dis-

played value on the scan tool.

NOTE: When this DTC is set and the system is fail-safe sta-
tus, the value of service data displays 20

°

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 8.
NO :  Go to Step 4.

STEP 4. Check ambient air temperature sensor connector 
A-25 for loose, corroded or damaged terminals, or 
terminals pushed back in the connector.

Q: Is ambient air temperature sensor connector A-25 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 g

to Step 8.

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC305210

A-25 (BR)

HARNESS SIDE

CONNECTOR: A-25

AP

 

 

 

 

 

 

 

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