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DTC B1691: Occupant sensing antenna
DTC B1693: Occupant sensing antenna open
DTC B1694: Occupant sensing ANT.SHT to GND
DTC B1695: Occupant sensing ANT.SHT to BAT
 
 
cautionIf DTC B1691, B1693, B1694 or B1695 is set in the occupant classification-ECU, always diagnose the CAN main bus lines.
 
 
CIRCUIT OPERATION
The load data from the occupant classification sensor is classified with the occupant classification-ECU, and its classified information is send to occupant classification-ECU. The SRS-ECU determines the air bag deployment based on this classified information, and controls the power supply circuit to the inflator.
 
 
DTC SET CONDITIONS
This DTC is set if the occupant classification sensor output voltage is out of the range (guideline: 1 to 3.5 V).
 
 
TROUBLESHOOTING HINTS
  • The occupant classification sensor may be defective.
  • Occupant classification-ECU may be defective.
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
 
 
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. Check whether the front passenger's seat is damped with liquid or steam.
Check whether the front passenger's seat is damped with liquid or steam.
Is the check result normal?
Go to Step 3.
Replace the front seat cushion cover and pad assembly (Refer to GROUP 52A, Front Seat Assembly ).
 
STEP 3. 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 4.
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP4. Check the harness wire for open circuit between the occupant classification-ECU connector D-48-2 (terminal No.11) and ground.
Is the check result normal?
Go to Step 5.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP5. Check the harness wires for open circuit and short circuit between the occupant classification-ECU connector D-38-1 (terminal No.2 and 5) and occupant classification sensor connector.
Is the check result normal?
Go to Step 6.
The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.
 
STEP 6. 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 ).
There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).