SRS AIR BAG DIAGNOSIS
TSB Revision
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
52B-113
CAUTION
If DTC B1417 is set in the SRS-ECU, always diag-
nose the CAN main bus line.
.
CIRCUIT OPERATION
The side impact sensor includes an analog G sensor
and CPU, etc. The CPU monitors the analog G sen-
sor output signal. If the CPU judges that the
side-airbags should be deployed, it sends a fire sig-
nal to the SRS-ECU to deploy the side-airbags. In
addition, the CPU diagnoses the internal compo-
nents of the side impact sensor. If a malfunction
occurs, it requests the SRS-ECU to set a diagnostic
trouble code.
.
DTC SET CONDITIONS
This DTC will set when the power supply voltage to
the front impact sensor (LH) remains less than a pre-
determined value for five seconds. However, if the
system returns to normal condition, code number
B1417 will be erased automatically and the SRS
warning light will go out.
.
TROUBLESHOOTING HINTS
• Damaged wiring harness or connectors
• Malfunction of the front air bag module (LH)
(squib)
• Malfunction of the SRS-ECU
.
DIAGNOSIS
Required Special Tools:
• MB991958: Scan Tool (MUT-III Sub Assembly)
• MB991824: Vehicle Communication Interface (V.C.I.)
• MB991827: MUT-III USB Cable
• MB991910: MUT-III Main Harness A (Vehicles with CAN
communication system)
• MB991223 (MB991222): Harness set (Probe)
STEP 1. Using scan tool MB991958, diagnose the CAN bus
line.
CAUTION
To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect the
scan tool
P.52B-30
."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES : Go to Step 2.
NO : Repair the CAN bus line (Refer to GROUP 54C,
Diagnosis
P.54C-14
).
AC305412
AB
MB991910
DATA LINK
CONNECTOR
MB991824
MB991827