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DTC U1100: Engine CAN timeout
 
 
caution
  • If DTC U1100 is stored in the SRS-ECU, diagnose the CAN main bus line.
  • Whenever the ECU is replaced, ensure that the communication circuit is normal.
 
 
DTC SET CONDITION
When the SRS-ECU cannot receive any signal (motor driving and selector lever position) from the engine control module for 500 milliseconds or more, it stores diagnostic trouble code No. U1100 (motor driving).
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the engine control module
  • Malfunction of the SRS-ECU
  • Malfunction of the CAN bus
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-III), diagnose the CAN bus line
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect the scan tool ."
(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.
Is the CAN bus line found to be normal?
Go to Step 2.
Repair the CAN bus line. (Refer to GROUP 54C, Diagnosis ).
 
STEP 2. Using scan tool (M.U.T.-III), read the other systems diagnostic trouble code.
Check if the DTC is stored in the engine control module.
Is the DTC stored?
Carry out troubleshooting of the engine control module (Refer to GROUP 13A, Troubleshooting ).
Go to Step 3.
 
STEP 3. Using scan tool (M.U.T.-III), read the other systems diagnostic trouble code.
Check if DTC U1100 is stored in the ETACS-ECU.
Is the DTC stored?
Go to Step 4.
Go to Step 5.
 
STEP 4. Check whether the diagnostic trouble code is stored again.
Check again if the DTC is stored in the SRS-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) On completion, check that the DTC is stored again.
Is the DTC stored?
Replace the engine control module. After replacing the ECU, carry out the CAN bus diagnostics. Then go to Step 6.
A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the engine control module and the SRS-ECU (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
 
STEP 5. Check whether the diagnostic trouble code is stored again.
Check again if the DTC is stored in the SRS-ECU.
(1) Erase the diagnostic trouble code.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) On completion, check that the DTC is not stored again.
Is the DTC stored?
Replace the SRS-ECU. After replacing the ECU, carry out the CAN bus diagnostics. Then go to Step 6.
A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the engine control module and the SRS-ECU (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
 
STEP 6. Recheck for diagnostic trouble code.
Check again if the DTC is stored in the SRS-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3) Check if DTC is stored.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC stored?
Return to Step 1.
The procedure is complete.