E7030 Airbag (Front Air BagSide)

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 sidebags 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 corresponding side Air Bag is activated (only on the side where the impact has taken 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 has two different levels of intervention for a frontal impact:

• at the first level only the pretensioners are activated
• the second level operates both airbags and pretensioners.

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 Air Bag on the side where the impact has taken place.

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.

The driver's Air Bag module is located in the centre of the steering wheel; it is mounted on a tilting plate which allows 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.

Ì

The passenger airbag may be deactivated manually via a special switch or automatically by a sensor in the seat.

The switch, which is ignition-activated, is located at the end of the facia on the passenger side and is accessible only with the door open. When the key is turned to OFF, the control unit also controls the activation of a passenger air bag disablement warning light.

Ì

The seat houses an automatic passenger presence detection sensor. This takes the form of electrical resistors that detect the presence or absence of a passenger.

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

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

It cuts in to take up the inevitable lengthening of the seat belt due to the action of the body in order to hold the body against the seat squab.

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
• to indicate the presence of faults via a warning light

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

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

The system control unit supply lines are protected by a fuse located next to the junction unit.

When operations are carried out to the Air Bag system the recommended safety instructions must be followed precisely. For more details See assembly drawing 5580C Air bag system

For a period, the passenger presence sensor has not been fitted; instead, while awaiting the modified control unit and wiring, the sensor has been temporarily replaced by a specific simulation resistor to ensure that the control unit self-test does not detect an error.

Description of operation

The control unit for the Air Bag system M60 is controlled by the ignition (INT) at pin 5 from a line protected by shunt fuse B32 up to 2/99 or by fuse F5 of supplementary fuse box B98A from 2/99.

Pin 40 is connected to a specific 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 airbag Q9, through a clockspring on the steering wheel Q10 (from pins 11 and 10):
• to passenger side air bag Q11 (from pins 13 and 14);
• to the pretensioners on the driver's side Q20 (from pins 1 and 2) and the passenger side Q21 (from pins 3 and 4).

ú

Pins 15 and 37 are connected to the sensor in the seat for disabling the passenger Air Bag K65.

Pins 6 and 12 are connected to the passenger Air Bag disabling switch H75.

Side impact detection sensors K66 (driver's side) and K67 (passenger side) send signals to pins 22, 24 and 23, 25 respectively of 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 16 and 17);
• to the passenger side Air Bag Q31 (from pins 18 and 19);

The two side Air Bags are connected to earth C50.

When the system autodiagnostic function detects a failure or an impact is detected, the control unit M60 sends a signal from pin 7 for the "Air Bag failure" warning light, located in check instrument E30. This signal turns on the warning light because instrument E30 is supplied via the ignition (INT) by a line protected by control lighting fuse B11 up to 2/99 or from fuse F4 of supplementary fuse box B98B from 2/99.

Self-diagnostic data may be read by connecting the unit to connector R10: this receives signals from pin 9 of control unit M60 through the appropriate tester line.

Pin 33 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 instrument E30 is supplied via the ignition (INT) from a line protected by the control light fuse B11 up to 2/99 or by fuse F4 of supplementary fuse box B98B from 2/99.

Wiring diagram

Components

Component location