vivaro phs 2 fooked!!

Hi all I've got a vivaro 1.6 14plate cat d. got it as a crash repairable 20k on the clock for £5k bargain .... the crash only took the passenger wing, head light, grill, bumper most of the plastic stuff out but no chassie dammage although the air bag poped an belt tensioner fired ??? came as non starter due to the airbags going off, now I've had air bag ECU reset a new bag and belt, but it still won't start !!!
Instead I have brake fault, hazard engine failure..... wtf !!!
Had a Renault...

vivaro phs 2 fooked!!