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DTC B1B8D: Driver Seat Slide Sensor Open Circuit
 
 
cautionIf DTC B1B8D is set in the occupant classification-ECU, always diagnose the CAN main bus lines.
 
 
CIRCUIT OPERATION
  • The seat slide sensor sets the current value Hi or Low determined by the seat position.
  • The occupant classification-ECU determines the seat position according to the current value from the seat slide sensor.
 
 
DTC SET CONDITIONS
  • This DTC is set if there is abnormal resistance between the input terminals of the seat slide sensor. The most likely causes for this code to be set are the followings:
    • Open circuit in the seat slide sensor or harness
 
 
TROUBLESHOOTING HINTS
  • Open circuit in the seat slide sensor circuit
  • Disengaged seat slide sensor connector
  • Improper connector contact
  • Malfunction of the seat slide sensor
  • Malfunction of the occupant classification-ECU
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
cautionTo prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
(1) 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. Recheck for diagnostic trouble code.
Check again if the DTC is set.
(1) Erase the DTC.
(2) Turn the ignition switch to the "ON" position.
(3) Check if the DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the DTC set?
Go to Step 3.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 3. Check the harness for open circuit between occupant classification-ECU connector D-48-2 (terminal No.27 and 29) and the seat slide sensor connector D-46 (terminal No.2 and 1).
(1) Disconnect occupant classification-ECU connector D-48-2 and seat slide sensor connector D-46.
(2)
cautionDo not insert a test probe into the terminal from its front side directly, as the connector contact pressure may be weakened.
Check for continuity between the following terminals. It should be less than 2 ohms.
  • Occupant classification-ECU connector D-48-2 (terminal No.27) and the seat slide sensor connector D-46 (terminal No.2)
  • Occupant classification-ECU connector D-48-2 (terminal No.29) and the seat slide sensor connector D-46 (terminal No.1)
Does continuity exist?
Go to Step 4.
Repair the harness wires between occupant classification-ECU connector D-48-2 and seat slide sensor connector D-46.
 
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set to 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 B1B8D set?
Replace the driver seat cushion frame assembly (Refer to GROUP 52A, Front seat assembly ). Then go to Step 5.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set to 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 passenger seat cushion frame assembly (Refer to GROUP 52A, Front seat assembly ).
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).