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DTC U15A2 Vehicle speed information lost
 
 
caution
  • If DTC U15A2 is set in the occupant classification-ECU, always diagnose the CAN bus line.
  • Before replacing the ECU, ensure that the communication circuit is normal.
 
 
TROUBLE JUDGMENT
If the signal from ASC-ECU cannot be received, the occupant classification-ECU sets DTC U15A2.
 
 
JUDGMENT CRITERIA
After the following statuses continue to be true for 5 seconds, if the communication with the ASC-ECU cannot be established for 0.6 second or more, the occupant classification-ECU determines that a problem has occurred.
  • No abnormality is present to the network.
  • Ignition switch is in the ON position.
  • No abnormality is present to the power supply fuse(IOD fuse), or the odometer value is at 80.5 km (50.0 miles) or more.
  • occupant classification-ECU system voltage is at 10-16 volts.
 
 
TROUBLESHOOTING HINTS
  • The ASC-ECU may be defective.
  • The occupant classification-ECU may be defective.
  • The CAN bus may be defective.
 
 
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 MB991958 ."
(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, check for any ASC diagnostic trouble code.
Check if DTC is set in the ASC-ECU.
Is the DTC set?
Troubleshoot the ASC. (Refer to GROUP 35C, Diagnosis .)
Go to Step 3.
 
STEP 3. Using scan tool MB991958, read the KOS-ECU diagnostic trouble code.
Check if DTC U1102 set in the KOS-ECU.
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 occupant classification-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 ASC-ECU.
The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the ASC-ECU and the occupant classification-ECU. (Refer to GROUP 00, How to Cope with Intermittent Malfunction )
 
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set in the occupant classification-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 front seat cushion cover and pad assembly (Refer to GROUP 52A, Front Seat Assembly ).
The trouble can be an intermittent malfunction such as a poor connection or open circuit in the CAN bus lines between the ASC-ECU and the occupant classification-ECU. (Refer to GROUP 00, How to Cope with Intermittent Malfunction )