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DTC U0100 ECM CAN timeout
 
 
caution
  • If DTC U0100 is set in the SRS-ECU, diagnose the CAN main bus line.
  • Whenever the ECU is replaced, ensure that the input and output signal circuits are normal.
 
 
TROUBLE JUDGMENT
If signal from the engine control module cannot be received for 500 milliseconds or more, the SRS-ECU sets DTC U0100.
 
 
PROBABLE CAUSES
  • Malfunction of the CAN bus
  • Malfunction of the engine control module
  • Malfunction of the SRS-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). 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.-IIISE), check whether the other system DTC is set.
Check the engine control module DTC.
Is the DTC set?
Diagnose the engine control module (Refer to GROUP 13A - Diagnosis ).
Go to Step 3.
 
STEP 3. Using scan tool (M.U.T.-IIISE), check whether the other system DTC is set.
Check the ETACS-ECU DTC U0100.
Is the DTC set?
Go to Step 4.
Go to Step 5.
 
STEP 4. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Check the DTC.
(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 set again.
Is the DTC set?
Replace the engine control module (Refer to GROUP 13A - Engine control module ). After replacing the ECU, carry out the CAN bus diagnostics
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. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Check the DTC.
(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 set again.
Is the DTC set?
Replace the SRS-ECU (Refer to ). After replacing the ECU, carry out the CAN bus diagnostics.
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 ).