Mitsubishi Outlander GS45X. Manual - part 1004

MANUAL A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55A-43

STEP 3. Using scan tool MB991958, check for any 
diagnostic trouble code.
Check if a DTC, which relates to CAN communication-linked 
systems below, is set.

• WCM <vehicles with WCM>

B2204: Coding data unmatched

• KOS <vehicles with KOS>

B2204: Coding data unmatched

(1) Turn the ignition switch to the "ON" position.
(2) Check for a DTC related to the relevant system.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?

YES : Go to Step 5.
NO :  Go to Step 4.

STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?

YES : A poor connection, open circuit or other intermittent 

malfunction is present in the lines between the 
ETACS-ECU and the A/C-ECU (Refer to GROUP 
00E, Harness Connector Inspection 

P.00E-2

.)

NO :   Replace the ETACS-ECU. On completion, check that 

the DTC is not reset.

STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the DTC is set.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?

YES : A poor connection, open circuit or other intermittent 

malfunction is present in the lines between the 
ETACS-ECU and the A/C-ECU (Refer to GROUP 
00E, Harness Connector Inspection 

P.00E-2

.)

NO :  Replace the A/C-ECU. On completion, check that the 

DTC is not reset.

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-44

DTC U0019: Bus Off (CAN1)

CAUTION

If DTC U0019is set in the A/C-ECU, diagnose the 
CAN main bus line.

CAUTION

Whenever the ECU is replaced, ensure that the 
communication circuit is normal.

.

TROUBLE JUDGMENT

DTC U0019 will be stored when the A/C-ECU ceases 
CAN communication (bus off) and then resumes the 
communication when the ignition switch is turned to 
the "LOCK" (OFF) position.

.

TECHNICAL DESCRIPTION (COMMENT) 

The wiring harness wire or connectors may have 
loose, corroded, or damage terminals, or terminals 
pushed back in the connector, or the A/C-ECU may 
be defective.

.

TROUBLESHOOTING HINTS

• Defective connector(s) or wiring harness

• Malfunction of the A/C-ECU

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB992006: Extra Fine Probe

•  MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus 
line

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. Refer to "How to connect the 

Scan Tool (M.U.T.-III) 

P.55A-7

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

YES : Go to Step 2.
NO :  Repair the CAN bus line. (Refer to GROUP 54C, 

Diagnosis 

P.54C-17

).

ZC501967

AC404789

AC701411AB

MB991824

MB991827

MB991910

Data link 
connector

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-45

STEP 2. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Connect scan tool MB991958 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 : There is an intermittent malfunction such as poor 

engaged connector(s) or open circuit (Refer to 
GROUP 00, How to Use Troubleshooting/Inspection 
Service Points 

− How to Cope with Intermittent 

Malfunctions 

P.00-15

.)

NO :  Replace the A/C-ECU. On completion, check that the 

DTC is not reset.

DTC U0141: ETACS-ECU Time-out

CAUTION

If DTC U0141 is set in the A/C-ECU, diagnose the 
CAN main bus line.

CAUTION

Whenever the ECU is replaced, ensure that the 
communication circuit is normal.

.

TROUBLE JUDGMENT

The A/C-ECU receives air conditioning opera-
tion-related signals from the ETACS-ECU via the 
CAN bus lines. If the ECU cannot receive any of the 
air conditioning control-related signals from the 
ETACS-ECU, the diagnostic trouble code U0141 is 
stored.

.

TECHNICAL DESCRIPTION (COMMENT) 

Current trouble

• Connector(s) or wiring harness in the CAN bus 

lines between the ETACS-ECU and the 
A/C-ECU, the power supply system to the 
ETACS-ECU, the ETACS-ECU itself, or the 
A/C-ECU may be defective.

Past trouble

• If DTC U0141 is stored as a past trouble, carry 

out diagnosis with particular emphasis on wiring 
and connector(s) in the CAN bus line between 
the A/C-ECU and the ETACS-ECU, and the 
power supply system to the ETACS-ECU. 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.
NOTE: For a past trouble, you cannot find it by 
the scan tool CAN bus diagnostics even if there is 
a failure in CAN bus lines. In this case, refer to 
GROUP 00, How to Use Troubleshooting/Inspec-
tion Service Points 

−

 How to Cope with Intermit-

tent Malfunctions 

P.00-15

) and check the CAN 

bus lines. You can narrow down the possible 
cause of the trouble by referring to the DTC, 
which is set regarding the CAN communica-
tion-linked ECUs (Refer to GROUP 54C, Expla-
nation about the scan too CAN bus diagnostics 

P.54C-16

).

.

TROUBLESHOOTING HINTS

• Malfunction of the A/C-ECU

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:

• MB991223: Harness Set

• MB992006: Extra Fine Probe

•  MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: V.C.I.

MANUAL A/C DIAGNOSIS

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HEATER, AIR CONDITIONING AND VENTILATION

55A-46

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus 
line

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. Refer to "How to connect the 

Scan Tool (M.U.T.-III) 

P.55A-7

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

YES : Go to Step 2.
NO :  Repair the CAN bus line. (Refer to GROUP 54C, 

Diagnosis 

P.54C-17

).

STEP 2. Using scan tool MB991958 read the ETACS-ECU 
diagnostic trouble code.
Check whether an ETACS-ECU DTCs are set or not.
(1) Turn the ignition switch to the "ON" position.
(2) Check for ETACS-ECU DTCs.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?

YES :  Go to Step 3.
NO :   Diagnose the ETACS-ECU (Refer to GROUP 54A, 

Diagnostic Trouble Code 

P.54A-733

).

STEP 3. Using scan tool MB991958, check for any 
diagnostic trouble code.
Check if a DTC, which relates to CAN communication-linked 
systems below, is set.

• Combination meter

DTC indicating a time-out error related to the engine or 
automatic transaxle control system

(1) Turn the ignition switch to the "ON" position.
(2) Check for a DTC related to the relevant system.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?

YES : Go to Step 5.
NO :  Go to Step 4.

ZC501967

AC404789

AC701411AB

MB991824

MB991827

MB991910

Data link 
connector