Airbag system fault
Q I have recently bought a project 2006 Renault Megane CC with the 1.6 VVT petrol engine, code K4M. The problem I’m having is that the airbag warning light is on, along with the orange spanner symbol. I have a Foxwell NT614 code reader that shows the active fault codes ‘DF071 Drivers front airbag circuit 2 open circuit’ and ‘DF072 Drivers front airbag circuit 1 open circuit’. The fault codes come straight back if I clear them with the scan tool.
Which airbag do these faults relate to? Is it the driver’s main steering wheel airbag, the seat side airbag or the seat base anti-submarine airbag? I assume that Renault know we drive on the right in the UK and that the codes do indeed refer to the driver’s side of the car! John Hardy
A Codes are very often referred to as ‘left’ and ‘right’, which allows easier diagnosis without worrying whether the vehicle is left- or right-hand drive. However, the codes ‘DF071’ and ‘DF072’ can only refer to the driver’s side as they indicate the steering wheel airbag or the connecting clockspring in the column are at fault. It would be unusual for the problem to be the airbag itself and I would expect to find the clockspring (called the ‘squib’ by Renault) to be the problem.
Before attempting to remove and replace the clockspring, the battery should be disconnected and the steering centralised. The plastic shroud on the steering column should be detached; it’s normally held in place by three T20 Torx scews. The airbag is held on the steering wheel from behind by two T20 Torx screws and, once these are undone, the airbag should lift away. The wire to the airbag has a central locking pin which should be gently prised out before attempting to remove the connector.
Loosen off the large T50 Torx bolt securing the steering wheel, ensuring that the steering wheel is loose before undoing the bolt completely. Mark the steering wheel position before removing it, to ensure that when it is replaced it goes back into the same position. You should then be able to see the clockspring/squib, which needs to be unscrewed before carefully disconnecting the wires.
The replacement unit will normally have a locking pin (usually red) to ensure that the spring is not disturbed before being fitted. This pin will need to be removed once the unit is fitted but before the steering wheel is replaced. As the circuit will now be complete, you should find that the codes and the light have been extinguished.