Supplemental Restraint Systems. Dtc B1653/35 Seat Position Airbag Sensor Circuit Malfunction

The seat position airbag sensor circuit consists of the center airbag sensor assembly, front seat inner belt assembly LH and the seat position airbag sensor.
DTC B1653/35 is recorded when a malfunction is detected in the seat position airbag sensor circuit.

DTC No.	DTC Detection Condition	Trouble Area
B1653/35	The center airbag sensor assembly receives a short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the seat position airbag sensor circuit for 2 seconds. Front seat inner belt assembly LH malfunction Seat position airbag sensor malfunction Center airbag sensor assembly malfunction	Floor wire Front seat inner belt assembly LH Seat position airbag sensor Center airbag sensor assembly

WIRING DIAGRAM

Corolla. Zre142 Aze141.Supplemental Restraint Systems.Airbag System.
Dtc
B1653/35 Seat Position Airbag Sensor Circuit Malfunction

INSPECTION PROCEDURE

1.CHECK CONNECTORS

Turn the ignition switch off.

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

Check that the connectors are properly connected to the center airbag sensor assembly, front seat inner belt assembly LH and the seat position airbag sensor.
OK:
The connectors are properly connected.
HINT:
If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

Disconnect the connectors from the center airbag sensor assembly, front seat inner belt assembly LH and the seat position airbag sensor.

Check that the connector terminals are not damaged.
OK:
The terminals are not deformed or damaged.

REPLACE WIRE HARNESS

OK

2.CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (OPEN)

Connect the connectors to the front seat inner belt assembly LH and floor wire.

Using SST, connect terminals 14 (LSP+) and 13 (LSP-) of connector B.
NOTICE:
Do not forcibly insert SST into the terminals of the connector when connecting the wire.

SST: 09843-18040

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Condition
Specified Condition
2 (LSP+) - 1 (LSP-)
Always
Below 1 Ω

Go to step 9

OK

3.CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT)

Disconnect SST from connector B.

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Condition
Specified Condition
2 (LSP+) - 1 (LSP-)
Always
1 MΩ or higher

Go to step 10

OK

4.CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT TO B+)

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

Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
Switch Condition
Specified Condition
2 (LSP+) - Body ground
Ignition switch ON
Below 1 V
1 (LSP-) - Body ground
Ignition switch ON
Below 1 V

Go to step 11

OK

5.CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT TO GROUND)

Turn the ignition switch off.

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

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Condition
Specified Condition
2 (LSP+) - Body ground
Always
1 MΩ or higher
1 (LSP-) - Body ground
Always
1 MΩ or higher

Go to step 12

OK

6.CHECK SEAT POSITION AIRBAG SENSOR

Connect the connectors to the center airbag sensor assembly and the seat position airbag sensor.

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

Turn the ignition switch to ON, and wait for at least 60 seconds.

Clear the DTCs stored in the memory (COROLLA_ZRE142 RM000000XFE0H1X.html).

Turn the ignition switch off.

Turn the ignition switch to ON, and wait for at least 60 seconds.

Check for DTCs (COROLLA_ZRE142 RM000000XFE0H1X.html).
OK:
DTC B1653/35 is not output.
HINT:
Codes other than DTC B1653/35 may be output at this time, but they are not related to this check.

Go to step 7

USE SIMULATION METHOD TO CHECK (COROLLA_ZRE142 RM000000XFD0GSX.html)

7.REPLACE SEAT POSITION AIRBAG SENSOR

Turn the ignition switch off.

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

Replace the seat position airbag sensor with a known good part (COROLLA_ZRE142 RM000000UWJ066X.html).
HINT:
Perform the following inspection using known good parts from another vehicle if possible.

NEXT

8.CHECK CENTER AIRBAG SENSOR ASSEMBLY

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

Turn the ignition switch to ON, and wait for at least 60 seconds.

Clear the DTCs stored in the memory (COROLLA_ZRE142 RM000000XFE0H1X.html).

Turn the ignition switch off.

Turn the ignition switch to ON, and wait for at least 60 seconds.

Check for DTCs (COROLLA_ZRE142 RM000000XFE0H1X.html).
OK:
DTC B1653/35 is not output.
HINT:
Codes other than DTC B1653/35 may be output at this time, but they are not related to this check.

REPLACE CENTER AIRBAG SENSOR ASSEMBLY (COROLLA_ZRE142 RM000000UWV074X.html)

END

9.CHECK FLOOR WIRE (OPEN)

Disconnect the floor wire from the front seat inner belt assembly LH.
HINT:
SST has already been inserted into connector B.

Measure the resistance according to the value(s) in the table below.

Standard Resistance:
for Power Seat:
Tester Connection
Condition
Specified Condition
L56-1 (LSP+) - L56-3 (LSP-)
Always
Below 1 Ω
for Manual Seat:
Tester Connection
Condition
Specified Condition
L48-1 (LSP+) - L48-3 (LSP-)
Always
Below 1 Ω

REPLACE FLOOR WIRE

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH (COROLLA_ZRE142 RM00000122H071X.html)

10.CHECK FLOOR WIRE (SHORT)

Disconnect the floor wire from the front seat inner belt assembly LH.

Measure the resistance according to the value(s) in the table below.

Standard Resistance:
for Power Seat:
Tester Connection
Condition
Specified Condition
L56-1 (LSP+) - L56-3 (LSP-)
Always
1 MΩ or higher
for Manual Seat:
Tester Connection
Condition
Specified Condition
L48-1 (LSP+) - L48-3 (LSP-)
Always
1 MΩ or higher

REPLACE FLOOR WIRE

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH (COROLLA_ZRE142 RM00000122H071X.html)

11.CHECK FLOOR WIRE (SHORT TO B+)

Turn the ignition switch off.

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

Disconnect the floor wire from the front seat inner belt assembly LH.

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

Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.

Standard Voltage:
for Power Seat:
Tester Connection
Switch Condition
Specified Condition
L56-1 (LSP+) - Body ground
Ignition switch ON
Below 1 V
L56-3 (LSP-) - Body ground
Ignition switch ON
Below 1 V
for Manual Seat:
Tester Connection
Switch Condition
Specified Condition
L48-1 (LSP+) - Body ground
Ignition switch ON
Below 1 V
L48-3 (LSP-) - Body ground
Ignition switch ON
Below 1 V

REPLACE FLOOR WIRE

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH (COROLLA_ZRE142 RM00000122H071X.html)

12.CHECK FLOOR WIRE (SHORT TO GROUND)

Disconnect the floor wire from the front seat inner belt assembly LH.

Measure the resistance according to the value(s) in the table below.

Standard Resistance:
for Power Seat:
Tester Connection
Condition
Specified Condition
L56-1 (LSP+) - Body ground
Always
1 MΩ or higher
L56-3 (LSP-) - Body ground
Always
1 MΩ or higher
for Manual Seat:
Tester Connection
Condition
Specified Condition
L48-1 (LSP+) - Body ground
Always
1 MΩ or higher
L48-3 (LSP-) - Body ground
Always
1 MΩ or higher

REPLACE FLOOR WIRE

REPLACE FRONT SEAT INNER BELT ASSEMBLY LH (COROLLA_ZRE142 RM00000122H071X.html)

Tester Connection	Condition	Specified Condition
2 (LSP+) - 1 (LSP-)	Always	Below 1 Ω

Tester Connection	Switch Condition	Specified Condition
2 (LSP+) - Body ground	Ignition switch ON	Below 1 V
1 (LSP-) - Body ground	Ignition switch ON	Below 1 V