Code No. U1116: KOS CAN timeout/Not equipped


caution If diagnosis code No.U1116 is set in the auto A/C controller assembly (A/C-ECU), diagnose the CAN main bus line.
caution Whenever the ECU is replaced, ensure that the communication circuit is normal.

TROUBLE JUDGEMENT
The auto A/C controller assembly (A/C-ECU) receives air conditioner control-related signals from the KOS&OSS-ECU via the CAN bus lines. If the ECU cannot receive any of the air conditioner control-related signals from the KOS&OSS-ECU, diagnosis code U1116 will be set.

COMMENTS ON TROUBLE SYMPTOM
Current trouble
  • Connector(s) or wiring harness in the CAN bus lines between the KOS&OSS-ECU and the A/C-ECU, the power supply system to the KOS&OSS-ECU, the KOS&OSS-ECU itself, or the auto A/C controller assembly (A/C-ECU) may be faulty.
Past trouble
  • Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the auto A/C controller assembly (A/C-ECU) and the KOS&OSS-ECU, and the power supply system to the KOS&OSS-ECU. 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 cannot 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 Malfunction 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 Diagnostic Flow ).
    caution If the ignition switch is turned to the ON position without starting the engine, the diagnosis code U1116 (past trouble) may be set to the auto A/C controller assembly (A/C-ECU) after three minutes.

PROBABLE CAUSES

  • Damaged wiring harness or connectors
  • Malfunction of the KOS&OSS-ECU
  • Malfunction of the auto A/C controller assembly (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?
Go to Step 2.
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 KOS&OSS-ECU-related diagnosis code is set.

Q. Is the diagnosis code set?
Diagnose the KOS&OSS-ECU. (Refer to GROUP 42B Troubleshooting ).
Go to Step 3.

STEP 3. M.U.T.-III other system diagnosis code
Check if a diagnosis code, which relates to CAN communication-linked systems below, is set.

  • ETACS-ECU
    U1116: KOS-related time-out diagnosis code

Q. Is the diagnosis code set?
Go to Step 4.
Go to Step 5.

STEP 4. Check whether the diagnosis code is set again.
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?
Replace the KOS&OSS-ECU, and then go to Step 6.
A poor connection, open circuit or other intermittent malfunction in the CAN bus line between the KOS&OSS-ECU and auto A/C controller assembly (A/C-ECU) (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 5. Check whether the diagnosis code is set again.
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?
Replace the auto A/C controller assembly (A/C-ECU), and then go to Step 6.
A poor connection, open circuit or other intermittent malfunction in the CAN bus line between the KOS&OSS-ECU and the auto A/C controller assembly (A/C-ECU) (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

STEP 6. Check whether the diagnosis code is set again.
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?
Return to Step 1.
The procedure is complete.