Toyota CH-R Service Manual: Seat Position Airbag Sensor Circuit Malfunction (B1653/35)

DESCRIPTION

The seat position airbag sensor circuit consists of the airbag sensor assembly and seat position airbag sensor.

DTC B1653/35 is stored when a malfunction is detected in the seat position airbag sensor circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Test Mode / Check Mode
B1653/35	Seat Position Airbag Sensor Circuit Malfunction	Any of the following conditions is met: The airbag sensor assembly detects a line short in the seat position airbag sensor circuit. The airbag sensor assembly detects a short to ground in the seat position airbag sensor circuit. The airbag sensor assembly detects a short to B+ in the seat position airbag sensor circuit. The airbag sensor assembly detects an open in the seat position airbag sensor circuit. Seat position airbag sensor malfunction Airbag sensor assembly malfunction	for LHD: Floor wire Front No. 2 seat wire LH Seat position airbag sensor Airbag sensor assembly for RHD: Floor wire Front seat wire RH Seat position airbag sensor Airbag sensor assembly	Does not apply to test/check mode

DTC Detection Conditions:

		Vehicle Condition
		Pattern 1	Pattern 2	Pattern 3	Pattern 4	Pattern 5	Pattern 6
Diagnosis Condition	Ignition switch ON	○	○	○	○	○	○
Malfunction Status	The airbag sensor assembly detects a line short in the seat position airbag sensor circuit	○	-	-	-	-	-
	The airbag sensor assembly detects a short to ground in the seat position airbag sensor circuit	-	○	-	-	-	-
	The airbag sensor assembly detects a short to B+ in the seat position airbag sensor circuit	-	-	○	-	-	-
	The airbag sensor assembly detects an open in the seat position airbag sensor circuit	-	-	-	○	-	-
	Seat position airbag sensor malfunction	-	-	-	-	○	-
	Airbag sensor assembly malfunction	-	-	-	-	-	○
Detection Time		-	-	-	-	-	-
Number of Trips		1 trip	1 trip	1 trip	1 trip	1 trip	1 trip

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

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PROCEDURE

1.	CHECK CONNECTORS

(a) Turn the ignition switch off.

(b) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(c) Check that the connectors are properly connected to the airbag sensor assembly and seat position airbag sensor. Also check that the connectors that link the front No. 2 seat wire LH and floor wire are properly connected.

OK:

The connectors are properly connected.

HINT:

If the connectors are not properly connected, reconnect the connectors and proceed to the next inspection.

(d) Disconnect the connectors from the airbag sensor assembly and seat position airbag sensor. Also disconnect the connectors that link the front No. 2 seat wire LH and floor wire.

(e) Check that the terminals of the connectors are not deformed or damaged.

OK:

The terminals are not deformed or damaged.

NG

REPLACE WIRE HARNESS

OK

2.	CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (OPEN)

(a) Connect the connectors that link the front No. 2 seat wire LH and floor wire.

*1 Seat Position Airbag Sensor *2 Airbag Sensor Assembly *3 Service Wire *a Front view of wire harness connector (to Airbag Sensor Assembly) *b Front view of wire harness connector (to Seat Position Airbag Sensor)

(b) Using a service wire, connect terminals 9 (LSP+) and 17 (LSP-) of connector B.

NOTICE:

Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
M101-4 (LSP+) - M101-3 (LSP-)	Always	Below 1 Ω

NG

REPLACE FLOOR WIRE

OK

3.	CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT)

(a) Disconnect the service wire from connector B.

*1 Seat Position Airbag Sensor *2 Airbag Sensor Assembly *a Front view of wire harness connector (to Seat Position Airbag Sensor)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
M101-4 (LSP+) - M101-3 (LSP-)	Always	1 MΩ or higher

NG

REPLACE FLOOR WIRE

OK

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

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

*1 Seat Position Airbag Sensor *2 Airbag Sensor Assembly *a Front view of wire harness connector (to Seat Position Airbag Sensor)

(b) Turn the ignition switch ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
M101-3 (LSP-) - Body ground	Ignition switch ON	Below 1 V
M101-4 (LSP+) - Body ground	Ignition switch ON	Below 1 V

(d) Turn the ignition switch off.

(e) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

NG

REPLACE FLOOR WIRE

OK

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

(a) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition M101-3 (LSP-) - Body ground Always 1 MΩ or higher M101-4 (LSP+) - Body ground Always 1 MΩ or higher

*1 Seat Position Airbag Sensor *2 Airbag Sensor Assembly *a Front view of wire harness connector (to Seat Position Airbag Sensor)

NG

REPLACE FLOOR WIRE

OK

6.

CHECK DTC

(a) Connect the connectors to the airbag sensor assembly and seat position airbag sensor.

*1 Seat Position Airbag Sensor *2 Airbag Sensor Assembly

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

(c) Clear the DTCs stored in memory.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(d) Turn the ignition switch off.

(e) Turn the ignition switch ON, and wait for at least 60 seconds.

(f) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

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.

OK

USE SIMULATION METHOD TO CHECK

NG

7.	CHECK SEAT POSITION AIRBAG SENSOR

(a) Turn the ignition switch off.

*1 Seat Position Airbag Sensor *2 Airbag Sensor Assembly

(b) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(c) Replace the seat position airbag sensor with a known good one.

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HINT:

Perform the following inspection using known good parts from another vehicle if possible.

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

(e) Clear the DTCs stored in memory.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(f) Turn the ignition switch off.

(g) Turn the ignition switch ON, and wait for at least 60 seconds.

(h) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

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.

(i) Turn the ignition switch off.

(j) Disconnect the cable from the negative (-) battery terminal.

CAUTION:

Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

(k) Restore the seat position airbag sensor that was installed for testing to its original location.

Click here

OK

REPLACE SEAT POSITION AIRBAG SENSOR

NG

REPLACE AIRBAG SENSOR ASSEMBLY