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DTC U1000: OSS-ECU CAN Timeout
 
 
caution
  • If the DTC U1000 is set, diagnose the CAN bus lines.
  • When replacing the ECU, always check that the SRS circuit is normal.
 
 
DIAGNOSTIC FUNCTION
If the signal from combination meter cannot be received, the SRS-ECU sets diagnostic trouble code No. U1000.
 
 
JUDGMENT CRITERIA
Because of the CAN-B bus circuit malfunction, if SRS-ECU becomes unable to perform the normal data transmission, SRS-ECU determines that an abnormality is present.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of CAN bus line
  • Malfunction of SRS-ECU
  • Malfunction of the OSS-ECU
 
 
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 OSS-ECU diagnostic trouble code
Check if the DTC is set to the OSS-ECU.
Is the DTC set?
Diagnose the OSS. Then go to Step 4.
Go to Step 3.
 
STEP 3. Using scan tool MB991958, read diagnostic trouble code No. U1000 for other system.
Check if the DTC U1000 is set in ETACS-ECU, occupant classification-ECU, combination meter, A/C-ECU, KOS-ECU or WCM, CAN box unit, radio and CD player, satellite radio tuner.
Is the DTC set?
Replace the OSS-ECU (Refer to GROUP 42B, ).
Go to Step 4.
 
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set to 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?
Replace the SRS-ECU.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to use Troubleshooting/inspection Service Points ).