Mitsubishi Lancer (4A9 engine). Manual - part 288
TROUBLESHOOTING
HEATER, AIR CONDITIONER AND VENTILATION
55A-33
STEP 5. Check whether the diagnosis code is
reset.
Recheck if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition switch: LOCK (OFF) to ON
(3) Check if the diagnosis code is set.
Q: Is the diagnosis code set?
YES :
Replace the A/C-ECU, and then go to Step
6.
NO :
A poor connection, open circuit or other
intermittent malfunction in the CAN bus line
between the WCM and the A/C-ECU (Refer
to GROUP 00
− How to Cope with
Intermittent Malfunction ).
STEP 6. Check whether the diagnosis code is
reset.
Recheck if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition switch: LOCK (OFF) to ON
(3) Check if the diagnosis code is set.
Q: Is the diagnosis code set?
YES :
Return to Step 1.
NO :
The procedure is complete.
Code No. U0184: Audio CAN time-out
CAUTION
If diagnosis code No.U0184 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 conditioner control-related
signals from the audio system via the CAN bus lines.
If the ECU cannot receive any of the air conditioner
control-related signals from the audio system, diag-
nosis code U0184 will be stored.
COMMENTS ON TROUBLE SYMPTOM
Current trouble
• Connector(s) or wiring harness in the CAN bus
lines between the audio system and the A/C-
ECU, the power supply system to the audio sys-
tem, the audio system itself, or the A/C-ECU may
be defective.
Past trouble
• Carry out diagnosis with particular emphasis on
connector(s) or wiring harness in the CAN bus
lines between the A/C-ECU and the audio sys-
tem, and the power supply system to the audio
system. For diagnosis procedures, refer to "How
to treat past trouble" (Refer to GROUP 00
− How
to Treat Past Trouble ).
NOTE: For a past trouble, you can not find it by the
M.U.T.-III CAN bus diagnostics even if there is
any failure in CAN bus lines. In this case, refer to
GROUP 00, How to Cope with Intermittent Mal-
function and check the CAN bus lines. You can
narrow down the possible cause of the trouble by
referring to the diagnosis code, which is set
regarding the CAN communication-linked ECUs
(Refer to GROUP 54C
−
CAN Bus Line Diagnos-
tic Flow ).
CAUTION
If the ignition switch is turned to the ON position
without starting the engine, the diagnosis code
U0184 (past trouble) may be set to the A/C-ECU
after three minutes.
PROBABLE CAUSES
• Damaged wiring harness or connectors
• Malfunction of the audio
• Malfunction of the A/C-ECU
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.
Q: Is the check result normal?
YES :
Go to Step 2.
NO :
Repair the CAN bus lines (Refer to GROUP
54C, Troubleshooting ). On completion, go
to Step 6.
STEP 2. M.U.T.-III other system diagnosis code
Check whether the audio-related diagnosis code is
set.
Q: Is the diagnosis code set?
YES :
Diagnose the audio. Refer to .
NO :
Go to Step 3