Supplementary restraint system (SRS) (page 2 of 2)

For 5 seconds at the beginning of each ignition cycle, and if a fault is detected, the airbag ECU illuminates the SRS warning lamp. To illuminate the lamp, the airbag ECU connects the yellow/red wire between the instrument pack (C233-11) and the airbag ECU (C256-7) to the black earth wire between the airbag ECU (C256-6) and the airbag ECU fixing on the transmission tunnel (C360-1).

The airbag ECU sends diagnostic signals and, during a collision, fire signals, through the airbag and pretensioner circuits.

Testbook communication with the airbag ECU is via a yellow/pink wire from the diagnostic socket (C040-7) to the airbag ECU (C256-9).