Toyota CH-R Service Manual: Short in Driver Side Squib Circuit (B1800/51-B1803/51)

DESCRIPTION

The driver side squib circuit consists of the airbag sensor assembly, spiral cable with sensor sub-assembly and horn button assembly.

The airbag sensor assembly uses this circuit to deploy the airbag when deployment conditions are met.

These DTCs are stored when a malfunction is detected in the driver side squib circuit.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Test Mode / Check Mode
B1800/51	Short in Driver Side Squib Circuit	Any of the following conditions is met: The airbag sensor assembly detects a line short in the driver side squib circuit during the primary check. Spiral cable with sensor sub-assembly malfunction Driver side squib malfunction Airbag sensor assembly malfunction	Instrument panel wire Spiral cable with sensor sub-assembly Driver side squib (Horn button assembly) Airbag sensor assembly	Applies to check mode
B1801/51	Open in Driver Side Squib Circuit	Any of the following conditions is met: The airbag sensor assembly detects an open in the driver side squib circuit. Spiral cable with sensor sub-assembly malfunction Driver side squib malfunction Airbag sensor assembly malfunction	Instrument panel wire Spiral cable with sensor sub-assembly Driver side squib (Horn button assembly) Airbag sensor assembly	Applies to check mode
B1802/51	Short to GND in Driver Side Squib Circuit	Any of the following conditions is met: The airbag sensor assembly detects a short to ground in the driver side squib circuit. Spiral cable with sensor sub-assembly malfunction Driver side squib malfunction Airbag sensor assembly malfunction	Instrument panel wire Spiral cable with sensor sub-assembly Driver side squib (Horn button assembly) Airbag sensor assembly	Applies to check mode
B1803/51	Short to B+ in Driver Side Squib Circuit	Any of the following conditions is met: The airbag sensor assembly detects a short to B+ in the driver side squib circuit. Spiral cable with sensor sub-assembly malfunction Driver side squib malfunction Airbag sensor assembly malfunction	Instrument panel wire Spiral cable with sensor sub-assembly Driver side squib (Horn button assembly) Airbag sensor assembly	Applies to check mode

DTC Detection Conditions (B1800/51):

		Vehicle Condition
		Pattern 1	Pattern 2	Pattern 3	Pattern 4
Diagnosis Condition	Ignition switch ON	○	○	○	○
Malfunction Status	The airbag sensor assembly detects a line short in the driver side squib circuit during the primary check	○	-	-	-
	Spiral cable with sensor sub-assembly malfunction	-	○	-	-
	Driver side squib malfunction	-	-	○	-
	Airbag sensor assembly malfunction	-	-	-	○
Detection Time		-	-	-	-
Number of Trips		1 trip	1 trip	1 trip	1 trip

DTC Detection Conditions (B1801/51):

		Vehicle Condition
		Pattern 1	Pattern 2	Pattern 3	Pattern 4
Diagnosis Condition	Ignition switch ON	○	○	○	○
Malfunction Status	The airbag sensor assembly detects an open in the driver side squib circuit	○	-	-	-
	Spiral cable with sensor sub-assembly malfunction	-	○	-	-
	Driver side squib malfunction	-	-	○	-
	Airbag sensor assembly malfunction	-	-	-	○
Detection Time		-	-	-	-
Number of Trips		1 trip	1 trip	1 trip	1 trip

DTC Detection Conditions (B1802/51):

		Vehicle Condition
		Pattern 1	Pattern 2	Pattern 3	Pattern 4
Diagnosis Condition	Ignition switch ON	○	○	○	○
Malfunction Status	The airbag sensor assembly detects a short to ground in the driver side squib circuit	○	-	-	-
	Spiral cable with sensor sub-assembly malfunction	-	○	-	-
	Driver side squib malfunction	-	-	○	-
	Airbag sensor assembly malfunction	-	-	-	○
Detection Time		-	-	-	-
Number of Trips		1 trip	1 trip	1 trip	1 trip

DTC Detection Conditions (B1803/51):

		Vehicle Condition
		Pattern 1	Pattern 2	Pattern 3	Pattern 4
Diagnosis Condition	Ignition switch ON	○	○	○	○
Malfunction Status	The airbag sensor assembly detects a short to B+ in the driver side squib circuit	○	-	-	-
	Spiral cable with sensor sub-assembly malfunction	-	○	-	-
	Driver side squib malfunction	-	-	○	-
	Airbag sensor assembly malfunction	-	-	-	○
Detection Time		-	-	-	-
Number of Trips		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.

Click here

PROCEDURE

1.	CHECK VEHICLE CONDITION

(a) Choose the model to be inspected.

Result	Proceed to
w/o Occupant Classification System	A
w/ Occupant Classification System	B

B

GO TO STEP 8

A

2.	CHECK CONNECTORS

(a) Turn the ignition switch off.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *4 Instrument Panel Wire

(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 horn button assembly, airbag sensor assembly and spiral cable with sensor sub-assembly.

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 horn button assembly, airbag sensor assembly and spiral cable with sensor sub-assembly.

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

OK:

The terminals are not deformed or damaged.

(f) Check that the spiral cable with sensor sub-assembly connector (on the horn button assembly side) is not loose, deformed or damaged.

OK:

The connector locking button is not disengaged, and the claw of the lock is not deformed or damaged.

(g) Check that the short springs of the activation prevention mechanisms of the instrument panel wire connector and spiral cable with sensor sub-assembly connector are not deformed or damaged.

OK:

The short springs are not deformed or damaged.

NG

REPLACE WIRE HARNESS

OK

3.	CHECK HORN BUTTON ASSEMBLY

(a) Connect the instrument panel wire to the airbag sensor assembly and spiral cable with sensor sub-assembly.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *a Front view of wire harness connector (to Horn Button Assembly)

(b) Connect SST (resistance 2.1 Ω) to connector E.

CAUTION:

Never connect a tester to the horn button assembly for measurement, as this may lead to a serious injury due to airbag deployment.

SST: 09843-18061

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

(d) Clear the DTCs stored in memory.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(e) Turn the ignition switch off.

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

(g) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B1800/51, B1801/51, B1802/51 or B1803/51 is not output.

HINT:

Codes other than DTCs B1800/51, B1801/51, B1802/51 and B1803/51 may be output at this time, but they are not related to this check.

(h) Turn the ignition switch off.

(i) 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.

(j) Disconnect SST from connector E.

OK

REPLACE HORN BUTTON ASSEMBLY

NG

4.	CHECK DRIVER SIDE SQUIB CIRCUIT

(a) Disconnect the instrument panel wire from the airbag sensor assembly.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *a Front view of wire harness connector (to Horn Button Assembly)

(b) Check for a short to B+ in the circuit.

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

(2) Turn the ignition switch ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
z2-2 - Body ground	Ignition switch ON	Below 1 V
z2-1 - Body ground	Ignition switch ON	Below 1 V

(4) Turn the ignition switch off.

(5) 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 for an open in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - z2-1	Always	Below 1 Ω

(d) Check for a short to ground in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - Body ground	Always	1 MΩ or higher
z2-1 - Body ground	Always	1 MΩ or higher

(e) Check for a short in the circuit.

(1) Release the activation prevention mechanism built into connector B.

Click here

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - z2-1	Always	1 MΩ or higher

(3) Restore the released activation prevention mechanism of connector B to the original condition.

NG

GO TO STEP 6

OK

5.

CHECK DTC

(a) Connect the connectors to the horn button assembly and airbag sensor assembly.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 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 B1800/51, B1801/51, B1802/51 or B1803/51 is not output.

HINT:

Codes other than DTCs B1800/51, B1801/51, B1802/51 and B1803/51 may be output at this time, but they are not related to this check.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE AIRBAG SENSOR ASSEMBLY

6.	CHECK INSTRUMENT PANEL WIRE

(a) Disconnect the instrument panel wire from the spiral cable with sensor sub-assembly.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *4 Instrument Panel Wire *a Front view of wire harness connector (to Spiral Cable with Sensor Sub-assembly)

(b) Check for a short to B+ in the circuit.

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

(2) Turn the ignition switch ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F30-1 (D+) - Body ground	Ignition switch ON	Below 1 V
F30-2 (D-) - Body ground	Ignition switch ON	Below 1 V

(4) Turn the ignition switch off.

(5) 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 for an open in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F30-1 (D+) - F30-2 (D-)	Always	Below 1 Ω

(d) Check for a short to ground in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F30-1 (D+) - Body ground	Always	1 MΩ or higher
F30-2 (D-) - Body ground	Always	1 MΩ or higher

(e) Check for a short in the circuit.

(1) Release the activation prevention mechanism built into connector B.

Click here

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F30-1 (D+) - F30-2 (D-)	Always	1 MΩ or higher

(3) Restore the released activation prevention mechanism of connector B to the original condition.

NG

REPLACE INSTRUMENT PANEL WIRE

OK

7.	CHECK SPIRAL CABLE WITH SENSOR SUB-ASSEMBLY

(a) Check for a short to B+ in the circuit. (1) Connect the cable to the negative (-) battery terminal. (2) Turn the ignition switch ON. (3) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Switch Condition Specified Condition z2-2 - Body ground Ignition switch ON Below 1 V z2-1 - Body ground Ignition switch ON Below 1 V (4) Turn the ignition switch off. (5) 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.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *4 Instrument Panel Wire *a Front view of wire harness connector (to Horn Button Assembly)

(b) Check for an open in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - z2-1	Always	Below 1 Ω

(c) Check for a short to ground in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - Body ground	Always	1 MΩ or higher
z2-1 - Body ground	Always	1 MΩ or higher

(d) Check for a short in the circuit.

(1) Release the activation prevention mechanism built into connector D.

Click here

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - z2-1	Always	1 MΩ or higher

(3) Restore the released activation prevention mechanism of connector D to the original condition.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE SPIRAL CABLE WITH SENSOR SUB-ASSEMBLY

8.	CHECK CONNECTORS

(a) Turn the ignition switch off.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *4 Instrument Panel Wire

(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 horn button assembly, spiral cable with sensor sub-assembly and airbag sensor assembly.

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 horn button assembly, spiral cable with sensor sub-assembly and airbag sensor assembly.

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

OK:

The terminals are not deformed or damaged.

(f) Check that the spiral cable with sensor sub-assembly connector (on the horn button assembly side) is not loose, deformed or damaged.

OK:

The connector locking button is not disengaged, and the claw of the lock is not deformed or damaged.

(g) Check that the short springs of the activation prevention mechanisms of the instrument panel wire connector and spiral cable with sensor sub-assembly connector are not deformed or damaged.

OK:

The short springs are not deformed or damaged.

NG

REPLACE WIRE HARNESS

OK

9.	CHECK HORN BUTTON ASSEMBLY

(a) Connect the instrument panel wire to the airbag sensor assembly and spiral cable with sensor sub-assembly.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *a Front view of wire harness connector (to Horn Button Assembly) *b Color: Light Green

(b) Connect SST (resistance 2.1 Ω) to connector E (light green connector).

CAUTION:

Never connect a tester to the horn button assembly for measurement, as this may lead to a serious injury due to airbag deployment.

SST: 09843-18061

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

(d) Clear the DTCs stored in memory.

Click here

Body Electrical > SRS Airbag > Clear DTCs

(e) Turn the ignition switch off.

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

(g) Check for DTCs.

Click here

Body Electrical > SRS Airbag > Trouble Codes

OK:

DTC B1800/51, B1801/51, B1802/51 or B1803/51 is not output.

HINT:

Codes other than DTCs B1800/51, B1801/51, B1802/51 and B1803/51 may be output at this time, but they are not related to this check.

(h) Turn the ignition switch off.

(i) 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.

(j) Disconnect SST from connector E.

OK

REPLACE HORN BUTTON ASSEMBLY

NG

10.	CHECK DRIVER SIDE SQUIB CIRCUIT

(a) Disconnect the instrument panel wire from the airbag sensor assembly.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *a Front view of wire harness connector (to Horn Button Assembly) *b Color: Light Green

(b) Check for a short to B+ in the circuit.

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

(2) Turn the ignition switch ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
z2-2 - Body ground	Ignition switch ON	Below 1 V
z2-1 - Body ground	Ignition switch ON	Below 1 V

(4) Turn the ignition switch off.

(5) 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 for an open in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - z2-1	Always	Below 1 Ω

(d) Check for a short to ground in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - Body ground	Always	1 MΩ or higher
z2-1 - Body ground	Always	1 MΩ or higher

(e) Check for a short in the circuit.

(1) Release the activation prevention mechanism built into connector B.

Click here

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - z2-1	Always	1 MΩ or higher

(3) Restore the released activation prevention mechanism of connector B to the original condition.

NG

GO TO STEP 12

OK

11.

CHECK DTC

(a) Connect the connectors to the horn button assembly and airbag sensor assembly.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 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 B1800/51, B1801/51, B1802/51 or B1803/51 is not output.

HINT:

Codes other than DTCs B1800/51, B1801/51, B1802/51 and B1803/51 may be output at this time, but they are not related to this check.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE AIRBAG SENSOR ASSEMBLY

12.	CHECK INSTRUMENT PANEL WIRE

(a) Disconnect the instrument panel wire from the spiral cable with sensor sub-assembly.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *4 Instrument Panel Wire *a Front view of wire harness connector (to Spiral Cable with Sensor Sub-assembly)

(b) Check for a short to B+ in the circuit.

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

(2) Turn the ignition switch ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
F30-1 (D+) - Body ground	Ignition switch ON	Below 1 V
F30-2 (D-) - Body ground	Ignition switch ON	Below 1 V

(4) Turn the ignition switch off.

(5) 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 for an open in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F30-1 (D+) - F30-2 (D-)	Always	Below 1 Ω

(d) Check for a short to ground in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F30-1 (D+) - Body ground	Always	1 MΩ or higher
F30-2 (D-) - Body ground	Always	1 MΩ or higher

(e) Check for a short in the circuit.

(1) Release the activation prevention mechanism built into connector B.

Click here

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
F30-1 (D+) - F30-2 (D-)	Always	1 MΩ or higher

(3) Restore the released activation prevention mechanism of connector B to the original condition.

NG

REPLACE INSTRUMENT PANEL WIRE

OK

13.	CHECK SPIRAL CABLE WITH SENSOR SUB-ASSEMBLY

(a) Check for a short to B+ in the circuit. (1) Connect the cable to the negative (-) battery terminal. (2) Turn the ignition switch ON. (3) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Switch Condition Specified Condition z2-2 - Body ground Ignition switch ON Below 1 V z2-1 - Body ground Ignition switch ON Below 1 V (4) Turn the ignition switch off. (5) 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.

*1 Horn Button Assembly *2 Spiral Cable with Sensor Sub-assembly *3 Airbag Sensor Assembly *4 Instrument Panel Wire *a Front view of wire harness connector (to Horn Button Assembly) *b Color: Light Green

(b) Check for an open in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - z2-1	Always	Below 1 Ω

(c) Check for a short to ground in the circuit.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - Body ground	Always	1 MΩ or higher
z2-1 - Body ground	Always	1 MΩ or higher

(d) Check for a short in the circuit.

(1) Release the activation prevention mechanism built into connector D.

Click here

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
z2-2 - z2-1	Always	1 MΩ or higher

(3) Restore the released activation prevention mechanism of connector D to the original condition.

OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE SPIRAL CABLE WITH SENSOR SUB-ASSEMBLY