Restraint > SRSCM > Troubleshooting > B1511 Buckle Switch Driver open or short to Battery

General Description

Seat-belt Buckle Switch(BS) is located in driver and passenger side seat. SRSCM checks if seatbelt is buckled by signal of BS. SRSCM controls air bag module and BPT differently in accordance with vehicle speed at the moment of collision and signal from BS.

DTC Description

The SRSCM sets DTC B1511 if there is a open circuit or short to power in BS harness.

DTC Detecting Condition

Item

Detecting Condition

Possible cause

DTC Strategy

•	Check current(PWM type)

•	Short to power in BS harness.

•	Open circuit in BBS harness.

•	Poor connection of connected part.

•	Faulty BS.

•	Faulty SRSCM.

Enable Conditions

•	Ignition "ON"

Threshold Value

•

I < 3 mA

Diagnostic
Time

Qualification

•	More than 1 sec.

De-Qualification

•	More than 2 sec.

Specification

Test Condition

Ampere (mA)

Ignition ON

•	Unbuckled (S/W OFF) : Approx . 4 ~ 7 mA

•	Buckled (S/W ON) : Approx. 12 ~ 18 mA

Schematic Diagram

Monitor Scantool Data

1.	Ignition "OFF", connect scantool.

2.	Ignition "ON" & Engine "OFF", select "Diagnostic Trouble Codes(DTC)" mode.

3.	Monitor diagnostic trouble code and present of trouble code.

4.	Using a scantool, clear the DTC.

Is DTC present problem ?

▶ Go to "W/Harness Inspection" procedure.

▶ Displaying nothing(no DTC) or DTC with label "H"(historical) shows that Fault is intermittent caused by poor contact in the part's and/or SRSCM connector or was repaired and SRSCM memory was not cleared.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
▶ Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

Terminal and Connector Inspection

1.	Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.	Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
	▶ Go to "Main harness circuit inspection" procedure.

Main harness Circuit Inspection (I)

1.	Ignition "OFF".

2.	Disconnect the battery (-) terminal cable from the battery and wait at least one minutes.

3.	Disconnect Seat-belt Buckle Switch connector and SRSCM main harness connector.

Measure resistance between of the Buckle switch wiring connector and SRSCM harness connector.

Specification : approx. 1 Ω below

Is the measured resistance within specifications?

	▶ Go to "Main harness circuit inspection" procedure.
	▶ Substitute the SRS main harness and check for proper operation. If the problem is corrected, replace SRS main harness and then go to "Verification of Vehicle Repair" procedure.

Main harness Circuit Inspection (II)

1.	Ignition "OFF".

2.	Disconnect the battery (-) terminal cable from the battery, and wait at least one minutes.

3.	Disconnect Seat-belt Buckle Switch connector and SRSCM main harness connector.

4.	Connect the battery (-) terminal cable to the battery and Ignition "ON" & Engine "OFF"

Measure voltage between terminal "High" of the Seat-belt Buckle Switch harness connector and chassis ground.

Specification : 0V

Is the measured voltage within specifications?

	▶ Go to "Component Inspection" procedure.
	▶ Substitute the SRS main harness and check for proper operation. If the problem is corrected, replace SRS main harness and then go to "Verification of Vehicle Repair" procedure.

Component Inspection

1.	Ignition "ON" & Engine "OFF" and Using a scantool, clear the DTC.

2.	Ignition "OFF".

3.	Disconnect the battery (-) terminal cable from the battery, and wait at least one minutes.

4.	Disconnect Seat-belt Buckle Switch connector.

5.	Substitute the Seat-belt Buckle Switch and check for proper operation.

Is DTC present problem ?

	▶ Substitute a known-good SRSCM, and check for proper operation. If the problem is corrected, replace SRSCM and then go to "Verification of Vehicle Repair" procedure.
	▶ Substitute a known-good Seat-belt Buckle Switch, and check for proper operation. If the problem is corrected, replace Seat-belt Buckle Switch and then go to "Verification of Vehicle Repair" procedure.

Verification of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.

1.	Connect scantool and select "Diagnostic Trouble Codes(DTC)" mode.

2.	Using a scantool, clear the DTC.

3.	Operate the vehicle within DTC Enable conditions in General information.

Are any DTC present ?

	▶ Go to the applicable troubleshooting procedure.
	▶ System is performing to specification at this time.