Honda Civic. Manual — part 32

the airbag would be minimal.

Front Passenger's Weight Sensors

The front passenger's weight sensors (M) are part of seat base. The front passenger's
weight sensors detect the weight on the seat, and send the information to the ODS
unit (N). If the total weight is about 65 lbs (30 kg) or less, the ODS unit sends a
signal to the SRS unit to prevent the passenger's airbag from deploying. When the
passenger's airbag is disabled, the passenger airbag cutoff indicator on the center
panel comes on to alert the driver that the front passenger's airbag will not deploy in
a front-end collision.

Driver's Seat Position Sensor

The driver's seat position sensor (O) is under the driver's seat on the left side. When
the driver's seat is moved to its full forward position, the deployment of the driver's
airbag is moderated to decrease its force of impact during a front-end collision.

Fig. 42: Identifying SRS Components Location
Courtesy of AMERICAN HONDA MOTOR CO., INC.

4-door shown; 2-door is similar.

Rear Safing Sensor

The rear safing sensor is located under the rear seat. The rear safing sensor performs
the same basic function as the safing sensor in the SRS unit. It measures sideways

2008 Honda Civic EX

2006-08 RESTRAINTS SRS (Supplemental Restraint System) - Civic (Except Hybrid)

G force, such as the force the vehicle would receive in a side collision in the rear,
and sends that information to the SRS unit. The SRS unit uses that information, and
the information from the second side impact sensors to determine the side that is
impacted and the force. If the threshold is met, the SRS unit deploys the side airbag,
the side curtain airbag and the seat belt tensioner on that side.

SIDE AIRBAG CUTOFF INDICATOR/ODS OPERATION

The indicator comes on if the front passenger's seat is occupied by a small adult or
child who is leaning into the deployment path, or an object (grocery bag, briefcase,
purse, etc.) is in the seat. This indicates the passenger's side airbag is off and will
not deploy; there is no problem with the side airbag. If the passenger sits upright or
moves to another seat, or you remove the object from the seat, the light should go
off. There will be some delay between the occupant's repositioning and when the
indicator will turn on or off.

PASSENGER AIRBAG CUTOFF INDICATOR

The indicator comes on if the weight of the front passenger is about 65 lbs (30 kg)
or less. This indicates the passenger's front airbag is off and will not deploy. The
front airbag is shut off to reduce the chance of airbag-caused injuries.

SRS OPERATION

The main circuit in the SRS unit senses and judges the force of impact and, if
necessary, ignites the inflator charges. If battery voltage is too low or power is
disconnected due to the impact, the voltage regulator and the back-up power circuit
will keep voltage at a constant level.

For the SRS to operate:

Seat Belt Tensioners and Seat Belt Buckle Tensioners

1. A front impact sensor, side impact sensor, or the rear safing sensor must

activate and send electric signals to the microprocessor.

2. The microprocessor must compute the signals and send them to the tensioners.
3. The charges must ignite and deploy the tensioners.

Driver's and Front Passenger's Airbag(s)

2008 Honda Civic EX

2006-08 RESTRAINTS SRS (Supplemental Restraint System) - Civic (Except Hybrid)

1. A front impact sensor must activate and send electric signals to the

microprocessor.

2. The microprocessor must compute the signals and send them to the airbag

inflator(s).

3. The inflators that receives signals must ignite and deploy the airbags.

Side Airbag(s)

1. Aside impact sensor must activate and send electric signals to the

microprocessor.

2. The microprocessor must compute the signals and send them to the side airbag

inflator(s). However, the microprocessor cuts off the signals to the front
passenger's side airbag if the SRS unit determines that the front passenger's
head is in the deployment path of the side airbag.

3. The inflator that receives the signal must ignite and deploy the side airbag.

Side Curtain Airbag(s)

1. Side impact sensor or the rear safing sensor must activate, and send electrical

signals to the microprocessor.

2. The microprocessor must compute the signals and send them to the side curtain

airbag and side airbag inflator(s).

3. The inflator that receives the signals must ignite and deploy the side curtain

airbag and side airbag at the same time.

2008 Honda Civic EX

2006-08 RESTRAINTS SRS (Supplemental Restraint System) - Civic (Except Hybrid)

Fig. 43: SRS - Wiring Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Self-diagnostic System

A self-diagnostic circuit is built into the SRS unit; when the ignition switch is
turned ON (II), the SRS indicator comes on and goes off after about 6 seconds if the
system is operating normally.

If the indicator does not come on, or does not go off after 6 seconds, or if it comes
on while driving, it indicates an abnormality in the system. The system must be
inspected and repaired as soon as possible.

For better serviceability, the SRS unit memory stores a DTC that relates to the
cause of the malfunction, and the unit is connected to the data link connector
(DLC). This information can be read with the HDS when it is connected to the DLC
(see GENERAL TROUBLESHOOTING INFORMATION).

NOTE:

Before you disconnect the negative cable from the battery
for troubleshooting, make sure you have the anti-theft code
for the audio system or the navigation system (if equipped).

2008 Honda Civic EX

2006-08 RESTRAINTS SRS (Supplemental Restraint System) - Civic (Except Hybrid)