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DTC U1000: OSS CAN Time-out
 
 
caution
  • If diagnostic trouble code No. U1000 is set, be sure to diagnose the CAN bus line.
  • When replacing the ECU, always check that the communication circuit is normal.
 
 
DIAGNOSTIC FUNCTION
If the signal from OSS-ECU cannot be received, the power liftgate control unit sets diagnostic trouble code No. U1000.
 
 
JUDGMENT CRITERIA
With the statuses that the ignition switch is at ON position, system voltage is 10 to 16 V (data from ETACS-ECU), and there is no malfunction to the power supply fuse, or odometer value is 80.5 km or more, if the communication with OSS-ECU cannot be established for 2,500 ms or more, the power liftgate control unit determines that a problem has occurred.
 
 
PROBABLE CAUSES
  • Malfunction of OSS-ECU
  • Malfunction of the power liftgate control unit
  • Malfunction of CAN bus line
 
 
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 power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (M.U.T-III).
Connect scan tool (M.U.T-III). Refer to "How to connect scan tool (M.U.T.-III) ."
(2) Turn the power supply mode of the engine switch to ON.
(3) Diagnose the CAN bus line.
(4) Turn the power supply mode of the engine switch to OFF.
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 system diagnostic trouble code.
Check again if the DTC is set in the OSS-ECU.
(1)
cautionTo prevent damage to scan tool (M.U.T-III), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (M.U.T-III).
Connect scan tool (M.U.T-III). Refer to "How to connect scan tool (M.U.T.-III) ."
(2) Erase the DTC.
(3) Turn the power supply mode of the engine switch to ON.
(4) Check if DTC is set.
(5) Turn the power supply mode of the engine switch to OFF.
Is the DTC set?
Diagnose the OSS-ECU. (Refer to GROUP 42B Troubleshooting .)
Go to Step 3.
 
STEP 3. Using scan tool (M.U.T-III), read the other system diagnostic trouble code.
Check if DTC U1000 is set in the KOS-ECU, SRS-ECU, combination meter, ETACS-ECU, MMCS, radio and CD player or A/C-ECU
(1)
cautionTo prevent damage to scan tool (M.U.T-III), always turn the power supply mode of the engine switch to the OFF position before connecting or disconnecting scan tool (M.U.T-III).
Connect scan tool (M.U.T-III). Refer to "How to connect scan tool (M.U.T.-III) ."
(2) Erase the DTC.
(3) Turn the power supply mode of the engine switch to ON.
(4) Check if DTC is set.
(5) Turn the power supply mode of the engine switch to OFF.
Is the DTC set?
Go to Step 4.
Go to Step 5.
 
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set in the power liftgate control unit.
(1) Erase the DTC.
(2) Turn the power supply mode of the engine switch from OFF to ON.
(3) Check if DTC is set.
(4) Turn the power supply mode of the engine switch from ON to OFF.
Is the DTC set?
Replace the OSS-ECU.
A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the OSS-ECU and the KOS-ECU (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
 
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set in the power liftgate control unit.
(1) Erase the DTC.
(2) Turn the power supply mode of the engine switch from OFF to ON.
(3) Check if DTC is set.
(4) Turn the power supply mode of the engine switch from ON to OFF.
Is the DTC set?
Replace the power liftgate control unit.
A poor connection, open circuit or other intermittent malfunction is present in the CAN bus lines between the OSS-ECU and the KOS-ECU (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).