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SRS / Airbag
ECU – DTC Troubleshooting Guide
Version: 14.0
Date: 14-February-2017
Prepared by:Airbag COC Review &
Approved by:Sanjeev VM
Page: 76 of 549
B0072-1A:- Passenger Seatbelt Pretensioner Deployment Control circuit resistance below
threshold
Overview:-
ISO Code
B00721A
Customer Symptom
SRS Warning Lamp continuously ON in Instrument Cluster.
Fault Effects (On Vehicle)
Passenger Seatbelt Pretensioner deployment not guaranteed, if
a crash happens
Lamp Status (If Any)
SRS Warning Lamp continuously ON in Instrument Cluster.
Fault Detection Condition
This fault gets logged if the circuit resistance of Passenger
Seatbelt Pretensioner is below the threshold value (1.1 Ohm)
after 4 seconds of cranking.
Normal Operating Condition
The minimum threshold for Passenger Seatbelt Pretensioner
Control circuit is 1.1 Ohm.
Probable Trouble Area
Related wiring Harness, connector or terminals
Passenger Seatbelt Pretensioner Module
Airbag ECU
Airbag Wiring Harness
Healing Condition
Minimum threshold resistance for Passenger Seatbelt
Pretensioner should be 1.1 Ohm.
Component Details:-
Seatbelt Pre-tensioners
:- Seatbelt Pre-tensioners retracts forcefully to adjust occupants into a safer seating position
when the airbags deploy. It is usually located in the B-pillar and is connected with the seat belt buckle assembly.
Airbag ECU
:- It is fitted in the floor of central console in the car. The Airbag Electronic Control Unit (ECU) controls
the deployment system to allow an appropriate igniting of the Airbags and belt pre-tensioners to restrain the Driver
and passengers.
Preliminary Checks:-
1. Check Battery Voltage (12 V & above)
2. Check for any faults in Airbag Warning Lamp indication in Instrument Cluster.
3. Ensure the proper locking of Airbag ECU wiring harness connectors in the vehicle by the locking sound.
Trouble Shooting:-