E7030 Airbag (Head-Bag)

Description

The car may be fitted with an electronically-controlled safety system that sets off the front seat belt pretensioners and the driver's Air Bag, passenger Air Bag and Side Bags in the case of frontal and/or side impact of a certain severity.

In the case of a side impact of a certain magnitude, the Side Bag and the corresponding Head Bag are activated (only on the side where the impact took place).

An electronic control unit manages the entire system by controlling all the components and activating the restraint systems (pretensioners and airbags) as necessary.

The control unit is located under the centre console and is rigidly fixed to the bodyshell: in this way the deceleration sensors located inside it are close to the centre of gravity and detect deceleration for the entire vehicle accurately.

There is an accelerometric sensor on the two front door pillars which, in the case of a side impact, transmits a signal to the control unit. This signal is also processed inside the control unit which, as a result, decides on the operation of the Side Bag and the Head Bag on the side where the impact has taken place.

The driver's Air Bag module is located in the centre of the steering wheel; it is fitted on a tilting plate which enables the horn to be operated. The plate houses a metal container which holds the folded airbag and a gas generator that inflates the bag.

A clock spring device allows the airbag module connection leads to turn with the steering wheel without the risk of breakage.

The passenger airbag is located on the facia, above the glove compartment., and is fastened directly to the car crossmember via a special bracket.

The passenger Air Bag can be manually deactivated via a special switch - which can be operated by a key - located at the end of the dashboard, passenger side and is only accessible with the door open. With the key in the OFF position, the control unit also controls the operation of the special 'passenger Air Bag disabled' warning light.

The Side Bag is housed in the outer part of the front seat. The sensor is located in the centre pillar.

The Head Bag consists of a curtain bag which inflates and places itself between the head of the occupants and the side windows. The Head Bag folded bag is located under the roof panel, whilst the rear pillar houses the gas generator. The Head Bag represents further protection for the occupants of the front seats because, in addition to the chest area which is already protected by the Side Bags, it also protects the head.

It also offers the first protection for the occupants of the rear seats.

The pretensioner is a device built into the front seat belt reel.

For more details see DESCRIPTION AND OPERATION: 5580C Air bag system

The control unit comes with a self-diagnostic function.

• it detects and memorizes any faults
• it recognizes the various components and the type of fault
• it signals the onset of these faults via the special warning light

System activations following a particularly serious impact are memorized by the control unit.

The system control unit supply line is protected by a fuse in the additional fuse box.

carefully observe the safety regulations when working on the airbag system. For more details See assembly drawing 5580C Air bag system

Description of operation

The Air Bag system control unit M60 receives a supply controlled by the ignition (INT) at pin 7 of connector A from the line protected by fuse F5 of the additional fuse box B98B.

Pin 6 of connector A is connected to the special earth C50.

When frontal impact of a certain severity (depending on the software setting) is detected, the control unit sends control signals to set off the modules:

• to driver's Air Bag Q9, through a clockspring on the steering wheel Q10 (from pins 13 and 14 of connector A):
• to passenger side air bag Q11 (from pins 15 and 16 of connector A):
• to the driver's pretensioner Q20 (from pins 13 and 14 of connector B) and the passenger pretensioner Q21 (from pins 15 and 16 of connector B).

Pin 11 of connector A is connected to the passenger Air Bag disabling switch H75.

The side impact detection sensors K66 (driver's side) and K67 (passenger side) send signals to pins 1, 2, 3 and 4 respectively of connector B of the control unit M60.

When side impact of a certain severity (dependent on the software setting) is detected, the control unit sends control signals to set off the modules:

• to the driver's side Air Bag Q30 (from pins 17 and 18 of connector B);
• to the passenger side Air Bag Q31 (from pins 19 and 20 of connector B);
• to the driver's Head Bag Q40 (from pins 21 and 22 of connector B);
• to the passenger Head Bag Q41 (from pins 23 and 24 of connector B).

The two side Air Bags are connected to earth C50.

When the system self-diagnostic function detects a fault or an impact is detected, control unit M60 sends a signal -from pin 17 of connector A - to the Air Bag faulty warning light located in the instrument panel E50. This signal causes the warning light to come on because the instrument E30 supply is controlled by the ignition (INT) from the line protected by fuse F4 of the additional fuse box B98B.

Self-diagnostic data can be read by connecting the unit to connector R10: it receives signals from pin 9 of connector A of the control unit M60 through the relevant tester line.

Pin 12 of connector A of M60 sends the signal for the 'passenger Air Bag disabled' warning light, located in the speedometer E10. This signal causes the warning light to come on because the instrument E30 supply is controlled by the ignition (INT) from the line protected by fuse 4 of the additional fuse box B98B.

Wiring diagram

Components

Component location