Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM000001PK8009X
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: B1797; Calibration Malfunction; 2007 MY LX470 [08/2006 -        ]

DTC

B1797

Calibration Malfunction

DESCRIPTION

  • DTC B1797 is output when either of the following occurs:
    • Zero point calibration is performed when the conditions for the calibration are not satisfied.
    • Zero point calibration has failed.

Condition for the zero point calibration:

Item

Condition

DTC

Not recorded

Front passenger seat

Vacant

Front passenger side buckle switch

OFF (The seat belt is not fastened)

ECU temperature

0 to 46°C (32 to 114.8°F)

Filtered pressure

38 to 75 count

DTC No.

DTC Detection Condition

Trouble Area

B1797

When one of following conditions is met:

  • Zero point calibration is performed when the conditions for the calibration are not satisfied.
  • Zero point calibration has failed.
  • There is no malfunction if this DTC is not output again after performing occupant classification system zero point calibration.
  • Front seat cushion assembly (Occupant classification sensor)

NOTICE:

Replace the occupant classification ECU, occupant classification sensor, seat cushion cover pad, seat cushion cover and seat cushion seat heater as a 5 part set (see supply set part no.).

HINT:

  • When DTC B1650/32 is detected as a result of troubleshooting for the supplemental restraint system, check the DTCs stored in the occupant classification ECU. When DTC B1797 is output, perform troubleshooting for the DTC.
  • Use the intelligent tester to check for DTCs of the occupant classification ECU, otherwise the DTC cannot be read.

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK FOR DTC

(a) Turn the ignition switch ON.

(b) Clear the DTCs stored in the memory 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR .

HINT:

First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

(c) Turn the ignition switch OFF.

(d) Turn the ignition switch ON, and wait for at least 10 seconds.

(e) Check the DTCs 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR .

OK:

DTC B1797 is output.

HINT:

DTCs other than B1797 may be output at this time, but they are not related to this check.

NO

END

YES

2.

READ VALUE USING INTELLIGENT TESTER (SPECIFIED CONDITION FOR ZERO POINT CALIBRATION)

(a) Connect the intelligent tester (with CAN VIM) to the DLC3.

(b) Turn the ignition switch ON.

(c) Using the intelligent tester, read the DATA LIST 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DATA LIST / ACTIVE TEST .

Occupant classification ECU

Item

Measurement Item/ Range (Display)

Normal Condition

Specified Condition for Zero Point Calibration

Diagnostic Note

RELATIVE PRESS

Pressure sensor output/

Min.: 0

Max.: 255

0 to 210

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)

-

#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 the range of specified condition for zero point calibration.

A

THERMISTOR TEMP does not correspond to the range of specified condition for zero point calibration.

B
B

GO TO STEP 6

A

3.

CHECK FOR DTC

HINT:

Check that the zero point calibration is completed normally. If either of the following occurs, DTC B1797 will be output (Refer to INITIALIZATION 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: INITIALIZATION ).

  • Zero point calibration is performed when the calibration conditions are not satisfied.
  • Zero point calibration has failed.

(a) Turn the ignition switch ON.

(b) Clear the DTCs stored in the memory 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR .

HINT:

First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor assembly.

(c) Turn the ignition switch OFF.

(d) Turn the ignition switch ON.

(e) Check the DTCs 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR .

OK:

DTC B1797 is not output.

NEXT

4.

PERFORM ZERO POINT CALIBRATION

(a) Connect the intelligent tester (with CAN VIM) to the DLC3.

(b) Turn the ignition switch ON.

(c) Using the intelligent tester, perform the zero point calibration 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: INITIALIZATION .

(d) Turn the ignition switch OFF.

(e) Turn the ignition switch ON.

(f) Clear the DTCs stored in the memory 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR .

HINT:

If DTCs are not cleared at this time, past DTCs will remain.

NEXT

5.

CHECK FOR DTC

(a) Turn the ignition switch ON.

(b) Clear the DTCs stored in the memory 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR .

HINT:

First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

(c) Turn the ignition switch OFF.

(d) Turn the ignition switch ON.

(e) Check the DTCs 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR .

OK:

DTC B1797 is not output.

HINT:

DTCs other than B1797 may be output at this time, but they are not related to this check.

NEXT

END

6.

REPLACE FRONT SEAT CUSHION (WITH OCCUPANT CLASSIFICATION SENSOR AND ECU)

(a) Turn the ignition switch OFF.

(b) Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.

(c) Replace the front seat cushion (with occupant classification sensor and ECU).

(d) Connect the cable to the negative (-) battery terminal.

(e) Turn the ignition switch ON.

(f) Clear the DTCs stored in the memory 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR .

HINT:

First clear DTCs stored in the occupant classification ECU and then in the center airbag sensor.

(g) Turn the ignition switch OFF.

(h) Turn the ignition switch ON.

(i) Using the intelligent tester, check the DTCs of the occupant classification ECU 2007 MY LX470 [08/2006 -        ]; SUPPLEMENTAL RESTRAINT SYSTEM: OCCUPANT CLASSIFICATION SYSTEM: DTC CHECK / CLEAR .

OK:

DTC is not output.

NEXT

END