Dtc B1157 (No. 1157): Air Bag Deployment Signal Input - Suzuki Swift Sport 2004 Service & Repair Manual

DTC Troubleshooting
Step
1 Check air bag communication circuit
1) Turn ignition switch to OFF position.
2) Disconnect connector from SDM referring to "SDM
Removal and Installation in Section 8B".
3) Disconnect connector from junction block assembly.
4) Turn ignition switch to ON position.
5) Measure voltage between "L29-37" terminal of SDM
connector and vehicle body ground.
Is voltage 0 V?
2 Check air bag communication circuit
1) Turn ignition switch to OFF position.
2) Connect connectors to junction block assembly.
3) Turn ignition switch to ON position.
4) Measure voltage between "L04-2" terminal of junction
block assembly connector and vehicle body ground.
Is voltage 4 – 6 V?
3 Check air bag communication circuit
1) Measure voltage between "L29-37" terminal of SDM
connector and vehicle body ground.
Is voltage 4 – 6 V?

DTC B1157 (No. 1157): Air Bag Deployment Signal Input

Wiring Diagram
Refer to "DTC B1150 (No. 1150): Air Bag Communication Circuit Malfunction".
DTC Detecting Condition and Possible Cause
DTC detecting condition
Air bag deployment signal is fed from SDM to BCM.
Flow Test Description
Step 1: Check DTC for SDM.
DTC Troubleshooting
Step
1 DTC check of SDM
1) Check DTC stored in SDM referring to "DTC Check in
Section 8B".
Is DTC B1021 detected?
Action
Action
Body Electrical Control System:
Yes
Go to Step 2.
Go to Step 3.
Substitute a known-
good SDM and recheck.
Possible cause
• Air bag component parts
• BCM malfunction
Yes
Go to "DTC B1021:
Front Air Bag Module
Deployed in Section
8B".
10B-20
No
Short to power supply in
air bag communication
circuit.
Short to ground in air
bag communication
circuit. If OK, substitute
a known-good BCM
(included in junction
block assembly) and
recheck.
Open or high resistance
in air bag
communication circuit.
S7RS0BA204011
No
Substitute a known-
good BCM (included in
junction block
assembly) and recheck.