Mitsubishi Evolution X. Manual - part 1279

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-67

STEP 2. Using scan tool MB991958 read the hands free 
module diagnostic trouble code.
Check whether an hands free module DTCs are set or not.
(1) Turn the ignition switch to the "ON" position.
(2) Check for hands free module DTCs.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Diagnose the hands free module (Refer to GROUP 

54A, Diagnostic Trouble Code).

NO :   Go to Step 3.

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.

• ETACS-ECU

DTC indicating a time-out error related to the hands free 
module 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 DTC set?

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

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 DTC set?

YES : Replace the SRS-ECU. On completion, check that 

the DTC is not reset.

NO :  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

.)

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-68

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 DTC set?

YES : Replace the A/C-ECU. On completion, check that the 

DTC is not reset.

NO :  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

.)

DTC U0245: Audio visual navigation unit CAN timeout

CAUTION

If DTC U0245 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 the air conditioning con-
trol-related signals from the hands-free module via 
the CAN bus lines. If any of the air conditioning con-
trol-related signals from the audio visual navigation 
unit cannot be received, the diagnostic trouble code 
U0245 is stored.

.

TECHNICAL DESCRIPTION (COMMENT) 

Current trouble

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

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

Past trouble

• If DTC U0245 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 audio visual navigation unit, 
and the power supply system to the audio visual 
navigation unit. 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-9

).

.

TROUBLESHOOTING HINTS

• Malfunction of the audio visual navigation unit

• Malfunction of the A/C-ECU

• Damaged harness wires and connectors

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-69

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.55-7

."

(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-14

).

STEP 2. Using scan tool MB991958 read the audio visual 
navigation unit diagnostic trouble code.
Check whether an audio visual navigation unit DTCs are set or 
not.
(1) Turn the ignition switch to the "ON" position.
(2) Check for audio visual navigation unit DTCs.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Diagnose the audio visual navigation unit (Refer to 

GROUP 54A, Diagnostic Trouble Code ).

NO :   Go to Step 3.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

AUTO A/C DIAGNOSIS

TSB Revision

HEATER, AIR CONDITIONING AND VENTILATION

55-70

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.

• ETACS-ECU

DTC indicating a time-out error related to the audio visual 
navigation unit 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 DTC set?

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

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 DTC set?

YES : Replace the audio visual navigation unit. On 

completion, check that the DTC is not reset.

NO :  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

.)

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 DTC set?

YES : Replace the A/C-ECU. On completion, check that the 

DTC is not reset.

NO :  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

.)