B1793
SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM (for Separate Seat Type): B1793: Occupant Classification Sensor Power Supply Circuit Malfunction
DTC B1793 - Occupant Classification Sensor Power Supply Circuit Malfunction
DESCRIPTION
The occupant classification sensor power supply circuit consists of the occupant classification ECU and the occupant classification sensors.
DTC B1793 is set when a malfunction is detected in the occupant classification sensor power supply circuit.
HINT:
- When DTC B1650/32 is detected as a result of troubleshooting the supplemental restraint system, perform troubleshooting for DTC B1793 of the occupant classification system.
- Use the Techstream to check for DTCs of the occupant classification ECU, otherwise the DTCs cannot be read.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
- If troubleshooting (wire harness inspection) is difficult to perform, remove the front RH seat assembly installation bolts to see the under surface of the seat cushion.
- In the above case, hold the seat so that it does not fall down. Holding the seat for a long period of time may cause problems, such as seat rail deformation. Hold the seat up only for as long as necessary.
PROCEDURE
1. CHECK DTC
(a) Turn the ignition switch to the ON position.
(b) Clear any DTCs stored in the memory (Reading and Clearing Diagnostic Trouble Codes).
HINT:
- First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
- Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
(c) Turn the ignition switch to the LOCK position.
(d) Turn the ignition switch to the ON position.
(e) Using the Techstream, check for DTCs of the occupant classification ECU (Reading and Clearing Diagnostic Trouble Codes).
OK:
DTC B1793 is not output.
HINT: DTCs other than B1793 may be output at this time, but they are not related to this check.
OK -- USE SIMULATION METHOD TO CHECK
NG -- Continue to next step.
2. CHECK CONNECT CONNECTORS
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Check that the connectors are properly connected to the occupant classification ECU and the occupant classification sensors.
OK:
The connectors are properly connected.
NG -- CONNECT CONNECTORS
OK -- Continue to next step.
3. CHECK CONNECTORS
(a) Check that the connectors (on the occupant classification ECU side and the occupant classification sensors side) are not damaged (Electronic Circuit Inspection Procedure).
OK:
The connectors are not deformed or damaged.
NG -- REPAIR OR REPLACE WIRE HARNESS
OK -- Continue to next step.
4. CHECK NO. 1 SEAT WIRE (TO B+)
(a) Disconnect the connectors from the occupant classification ECU and the 4 occupant classification sensors.
(b) Connect the negative (-) terminal cable to the battery.
(c) Turn the ignition switch to the ON position.
(d) Measure the voltage.
Standard voltage:
NG -- REPAIR OR REPLACE NO. 1 SEAT WIRE
OK -- Continue to next step.
5. CHECK NO. 1 SEAT WIRE (TO GROUND)
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Measure the resistance.
Standard resistance:
NG -- REPAIR OR REPLACE NO. 1 SEAT WIRE
OK -- Continue to next step.
6. CHECK NO. 1 SEAT WIRE (FOR OPEN)
(a) Measure the resistance.
Standard resistance:
NG -- REPAIR OR REPLACE NO. 1 SEAT WIRE
OK -- Continue to next step.
7. CHECK NO. 1 SEAT WIRE (FOR SHORT)
(a) Measure the resistance.
Standard resistance:
NG -- REPAIR OR REPLACE NO. 1 SEAT WIRE
OK -- Continue to next step.
8. CHECK DTC
(a) Connect the connectors to the occupant classification ECU and the 4 occupant classification sensors.
(b) Connect the negative (-) terminal cable to the battery.
(c) Turn the ignition switch to the ON position.
(d) Clear any DTCs stored in the memory (Reading and Clearing Diagnostic Trouble Codes).
HINT:
- First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.
- Use the Techstream to clear the DTCs of the occupant classification ECU, otherwise the DTCs cannot be cleared.
(e) Turn the ignition switch to the LOCK position.
(f) Turn the ignition switch to the ON position.
(g) Using the Techstream, check for DTCs of the occupant classification ECU (Reading and Clearing Diagnostic Trouble Codes).
OK:
DTC B1793 is not output.
HINT: DTCs other than B1793 may be output at this time, but they are not related to this check.
OK -- USE SIMULATION METHOD TO CHECK
NG -- Continue to next step.
9. REPLACE OCCUPANT CLASSIFICATION ECU
(a) Turn the ignition switch to the LOCK position.
(b) Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
(c) Replace the occupant classification ECU.
HINT: Perform the inspection using parts from a normal vehicle when possible.
NEXT -- Continue to next step.
10. PERFORM ZERO POINT CALIBRATION
(a) Connect the negative (-) terminal cable to the battery.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Using the Techstream, perform the zero point calibration (Programming and Relearning).
OK:
"Zero Point Calibration is complete." is displayed on the Techstream.
NEXT -- Continue to next step.
11. PERFORM SENSITIVITY CHECK
(a) Using the Techstream, perform the sensitivity check (Programming and Relearning).
Standard:
27 to 33 kg (59.52 to 72.75 lb)
NEXT -- USE SIMULATION METHOD TO CHECK