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DTC U0100: Engine 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 communication circuit is normal.
 
 
DIAGNOSTIC FUNCTION
If signal from the engine control module cannot be received for 500 milliseconds or more, the SRS-ECU sets DTC U0100.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the engine control module
  • Malfunction of the SRS-ECU
  • Malfunction of the CAN bus
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line
(1)
cautionTo prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
Connect scan tool MB991958. 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 MB991958, read the other systems diagnostic trouble code.
Check if the DTC is set in the engine control module.
Is the DTC set?
Troubleshoot the engine (Refer to GROUP 13A - DTC Chart <2.0 L ENGINE>, GROUP 13C - DTC Chart <2.4 L ENGINE>)
Go to Step 3.
 
STEP 3. Using scan tool MB991958, read the other systems diagnostic trouble code.
Check if DTC U0100 is set in the ETACS-ECU.
Is the DTC set?
Go to Step 4.
Go to Step 5.
 
STEP 4. Check whether the diagnostic trouble code is set again.
Check again if the DTC is set 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 set again.
Is the DTC set?
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 set again.
Check again if the DTC is set 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 set again.
Is the DTC set?
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 set 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 set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC set?
Return to Step 1.
The procedure is complete.