DTC B1797: Calibration Malfunction: Procedure

WARNING: This page is about a different car, the 2009 Lexus GS 460 and 2009 Lexus GS 350. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FOR DTC
1. Turn the engine switch on (IG).
2. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
3. Clear the DTCs stored in the center airbag sensor. Refer to DTC CHECK / CLEAR .
4. Turn the engine switch off.
5. Turn the engine switch on (IG), and wait for at least 10 seconds.
6. Check for the DTCs. Refer to DTC CHECK / CLEAR .
  OK
  
  DTC B1797 is not output.
  
  HINT:
  
  Codes other than B1797 may be output at this time, but they are not related to this check.
OK → See step 7

NG: Go to next step

READ VALUE USING DATA LIST (SPECIFIED CONDITION FOR ZERO POINT CALIBRATION)

Connect the Techstream to the DLC3.
Turn the engine switch on (IG).

Using the Techstream, read the DATA LIST. Refer to DATA LIST / ACTIVE TEST .

OCCUPANT CLASSIFICATION ECU:

Tester Display	Measurement Item/ Range	Normal Condition	Specified Condition for Zero Point Calibration	Diagnostic Note
RELATIVE PRESS	Pressure sensor output / Min.: 0, Max.: 255	0 to 210 (reference value)	0 to 2	-
THERMISTOR TEMP	Thermistor temperature output / Min.: -40°C (-40°F), Max.: 90°C (194°F)	-40 to 85°C (-40 to 185°F)	3 to 40°C (36 to 104°F)	If value is outside range of Specified Condition for Zero Point Calibration, check whether any objects placed on seat cushion and that seat cushion fitted correctly
#PRESENT CODES	Number of present trouble codes / Min.: 0, Max.: 255	0	0	-
#PAST CODES	Number of past trouble codes / Min.: 0, Max.: 255	0	0	-

RESULT:

Result	Proceed to
All items correspond to range of specified condition for zero point calibration	A
THERMISTOR TEMP does not correspond to range of specified condition for zero point calibration	B

B → See step 6

A: Go to next step

CHECK FOR DTC
HINT:

Check that the zero point calibration is completed normally. If any of the following condition is met, DTC B1797 will be output (refer to INITIALIZATION: Refer to INITIALIZATION ).
- Zero point calibration is performed when the calibration conditions are not satisfied.
- Zero point calibration has failed.
1. Turn the engine switch on (IG).
2. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
3. Clear the DTCs stored in the center airbag sensor. Refer to DTC CHECK / CLEAR .
4. Turn the engine switch off.
5. Turn the engine switch on (IG).
6. Check for the DTCs. Refer to DTC CHECK / CLEAR .
  OK
  
  DTC B1797 is not output.
NEXT: Go to next step
PERFORM ZERO POINT CALIBRATION
1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Using the Techstream, perform the zero point calibration. Refer to INITIALIZATION .
4. Turn the engine switch off.
5. Turn the engine switch on (IG).
6. Clear the DTCs stored in the memory. Refer to DTC CHECK / CLEAR .
  HINT:
  
  If the DTCs are not cleared at this time, past DTCs will remain.
NEXT: Go to next step
CHECK FOR DTC
1. Turn the engine switch on (IG).
2. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
3. Clear the DTCs stored in the center airbag sensor. Refer to DTC CHECK / CLEAR .
4. Turn the engine switch off.
5. Turn the engine switch on (IG).
6. Check for the DTCs. Refer to DTC CHECK / CLEAR .
  OK
  
  DTC B1797 is not output.
  
  HINT:
  
  Codes other than B1797 may be output at this time, but they are not related to this check.
NEXT → END
REPLACE OCCUPANT DETECTION SENSOR (FRONT SEAT CUSHION ASSEMBLY)
1. Turn the engine switch off.
2. Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. Replace the front seat cushion (with occupant classification ECU and occupant detection sensor). Refer to DISASSEMBLY .
4. Connect the negative (-) terminal cable to the battery.
5. Turn the engine switch on (IG).
6. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
7. Clear the DTCs stored in the center airbag sensor. Refer to DTC CHECK / CLEAR .
8. Turn the engine switch off.
9. Turn the engine switch on (IG).
10. Using the Techstream, check for the DTCs of the occupant classification ECU. Refer to DTC CHECK / CLEAR .
  OK
  
  DTC is not output.
NEXT: Go to next step
PERFORM ZERO POINT CALIBRATION
1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Using the Techstream, perform the zero point calibration. Refer to INITIALIZATION .
4. Turn the engine switch off.
5. Turn the engine switch on (IG).
6. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
  HINT:
  
  If the DTCs are not cleared at this time, past DTCs will remain.
NEXT: Go to next step
CHECK FOR DTC
1. Turn the engine switch on (IG).
2. Clear the DTCs stored in the occupant classification ECU. Refer to DTC CHECK / CLEAR .
3. Clear the DTCs stored in the center airbag sensor. Refer to DTC CHECK / CLEAR .
4. Turn the engine switch off.
5. Turn the engine switch on (IG).
6. Check for the DTCs. Refer to DTC CHECK / CLEAR .
  OK
  
  DTC B1797 is not output.
NEXT: Go to next step
PERFORM SENSITIVITY CHECK
1. Perform the sensitivity check. Refer to INITIALIZATION .
NEXT → END