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Code No. U1116: KOS CAN timeout/Not equipped
cautionIf diagnostic trouble code No.U1116 is set in the auto A/C controller assembly (A/C-ECU), diagnose the CAN main bus line.
cautionWhenever the ECU is replaced, ensure that the communication circuit is normal.
 
 
 
 
TROUBLE JUDGMENT
The auto A/C controller assembly (A/C-ECU) receives air conditioning control-related signals from the KOS&OSS-ECU via the CAN bus lines. If the ECU cannot receive any of the air conditioning control-related signals from the KOS&OSS-ECU, diagnostic trouble 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 ).
    noteFor a past trouble, you cannot find it by the scan tool MB991958 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 diagnostic trouble code, which is set regarding the CAN communication-linked ECUs (Refer to GROUP 54C - CAN Bus Line Diagnostic Flow ).
    cautionIf the ignition switch is turned to the "ON" position without starting the engine, diagnostic trouble code U1116 (past trouble) may be set in 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
STEP 1. Using SCAN tool (M.U.T.-III), diagnose the CAN bus lines.
Use the scan tool (M.U.T.-III) to diagnose the CAN bus lines.
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. Check whether the diagnostic trouble code is set.
Check whether the KOS&OSS-ECU-related diagnostic trouble code is set.
Is the diagnostic trouble code set?
Diagnose the KOS&OSS-ECU. (Refer to GROUP 42B Troubleshooting ).
Go to Step 3.
 
STEP 3. Check whether the diagnostic trouble code is set again.
Check if a diagnostic trouble code, which relates to CAN communication-linked systems below, is set.
  • ETACS-ECU
    U1116: KOS-related time-out diagnostic trouble code
Is the diagnostic trouble code set?
Go to Step 4.
Go to Step 5.
 
STEP 4. Check whether the diagnostic trouble code is set again.
Recheck if the diagnostic trouble code is set.
(1) Erase the diagnostic trouble code.
(2) Ignition switch: "LOCK" (OFF) to "ON"
(3) Check if the diagnostic trouble code is set.
Is the diagnostic trouble 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 diagnostic trouble code is set again.
Recheck if the diagnostic trouble code is set.
(1) Erase the diagnostic trouble code.
(2) Ignition switch: "LOCK" (OFF) to "ON"
(3) Check if the diagnostic trouble code is set.
Is the diagnostic trouble 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 diagnostic trouble code is set again.
Recheck if the diagnostic trouble code is set.
(1) Erase the diagnostic trouble code.
(2) Ignition switch: "LOCK" (OFF) to "ON"
(3) Check if the diagnostic trouble code is set.
Is the diagnostic trouble code set?
Return to Step 1.
The procedure is complete.