SRS Ignition Signal and Wiring

Electrical Signal For Activating Airbags/seat Belt Tensioners
Ignition Signal (AC) SRS Airbag 6.2




To activate the igniters that deploy the airbags/seat belt tensioners, the sensor module transmits pulses in the form of AC signals through the ignition cables. At least 5 pulses are required to trigger an igniter.

A capacitor, built into the connector between the SRS ignition cable and the airbags/seat belt tensioners, allows this pulsing signal to pass through it while blocking a DC signal.

This means that connected airbags/seat belt tensioners in the SRS 6.2 system cannot be activated by unintentionally connecting a DC voltage during fault-tracing. This protection ceases when the SRS ignition cable connector is disconnected from the airbag/seat belt tensioner, as the capacitor is in the SRS ignition cable connector.

WARNING: Under no circumstances use an ohmmeter or other live measuring instrument to take readings on a disconnected non-deployed airbag/seat belt tensioner. This could deploy the airbag/seat belt tensioner.




Cabling between the sensor module and airbags/seat belt tensioners
The connector between the SRS ignition cable and airbags/seat belt tensioners has a built in capacitor (1). The capacitor is connected in series with one of the cables. Resistance cannot be measured between sockets (3) and (4) as the capacitor blocks measurement. There is an "service hole" (2) in the connector to facilitate fault-tracing.

The built-in capacitor prevents the unintentional triggering of the igniter due to the unintentional connection of a DC voltage to the SRS ignition cable.

NOTE: Always follow the instructions contained in the fault-tracing sections when tracing faults.

Repairing SRS cabling:

WARNING: SRS cabling must not be repaired or spliced and individual cables may not be replaced. If there is a fault in the cabling the SRS ignition cable and/or cable harness must be replaced.