When a vehicle crashes with a certain degree of frontal impact, the gas generator will ignited an electrical firing signal from the SRSCM (Supplemental Restraint System Control Module). Gas from the gas generator causes movement of the piston in the manifold case (cylinder), which operates the rack gear. The rack gear, rotates a piston gear and a pinion rotates the planet gears. Finally, the webbing is retracted by the rotation of the spool. Therefore, the pretensioner seat belt helps to reduce the severity of injury to the front seat occupant by retracting the seat belt webbing. This prevents the occupant from thrusting forward and hitting the steering wheel or the instrument panel when the vehicle crashes. The SRS harness is wrapped in a yellow tube to be discriminated from other system harnesses. A shorting bar is included inside the wiring connectors of DAB, PAB, SAB and BPT inflator side. The shorting bar shorts the current flow the DAB, PAB, SAB and BPT module circuits when the connectors are disconnected. The circuits to the inflator module are shorted in this way to help prevent unwanted deployment of the airbag when servicing the airbag module.
The PBPT squib circuit consists of the SRSCM and PBPT. If it causes the PBPT to deploy when the PBPT deployment conditions are satisfied. The above DTCs are recorded when the resistance too low is detected in the PBPT squib circuit.
Item
Detecting Condition
Possible Cause
DTC Strategy
? Check current
? Short PBPT circuit.
? Faulty PBPT.
? Faulty SRSCM.
Enable Conditions
? Ignition "ON"
Threshold Value
? PBPT resistance = 0.9 ?
? Tolerance band : 0.9 ? < Rs < 1.8 ?
Diagnostic Time
Qualification
? More than 4 sec
De-Qualification
? More than 9.6 sec
? The SRS current measuring can be cause of component malfunction. So the current value is not mentioned in Threshold value to prohibit measuring the current.
? Tolerance band : It is unstable band that ECM detects the failure or not to do.
PBPT circuit resistance(O)
1.8 ? < Rs < 3.1 ?