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Acura RL. Manual - part 114

one side airbag will deploy during a side impact. If the impact is on the passenger's side, the passenger's side
airbag will deploy even if there is no passenger.

Side Curtain Airbags

The side curtain airbags (L) are in each side of the roof. They help protect the head of the driver, front
passenger, and passengers in the rear outer seats during a moderate to severe side impact. Side impact
sensors (first) (F) in each front door sill, side impact sensors (second) (K) in each rear door sill, rear safing
sensor (P) under the rear seat, and the SRS unit detect such an impact and instantly inflate the driver's or the
passenger's side curtain airbag. A side impact causes the side curtain airbag and the side airbag on the
impacted side to deploy at the same time.

Seat Belt Tensioners

The seat belt tensioners are linked with the SRS airbags to further increase the effectiveness of the seat belt.
In a front-end collision, the tensioners instantly retract the belt firmly to secure the driver and front
passenger in their seats.

OPDS

The side airbag system also includes an occupant position detection system (OPDS). This system consists of
sensors (G) and a OPDS unit (H) in the front passenger's seat-back. The OPDS unit sends occupant height
and position data to the SRS unit. If the OPDS unit determines that the front passenger is of small stature
(for example, a child) or the front passenger is leaning into the side airbag deployment path, the SRS unit
will automatically disable the passenger's side airbag. The SRS unit will also disable the airbag when the
OPDS detects certain objects on the seat. When the side airbag is disabled, the side airbag cutoff indicator
on the instrument panel alerts the driver that the passenger's side airbag will not deploy in a side impact.
When the object is removed, or the passenger sits upright, the side airbag cutoff indicator will go off after a
few seconds, alerting the driver that the passenger's side airbag will deploy in a side impact.

SIDE AIRBAG CUTOFF INDICATOR/OPDS 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 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

2007 Acura RL

2005-08 RESTRAINTS SRS (Supplemental Restraint System) - RL

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Seat Belt Tensioners

1. A front impact sensor or side impact 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)

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. A side 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 OPDS unit
determines if the front passenger's seat is occupied by a small adult or a child who is leaning into the
deployment path, or if an object (grocery bag, briefcase, purse, etc.) 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 sensors 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.

2007 Acura RL

2005-08 RESTRAINTS SRS (Supplemental Restraint System) - RL

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Fig. 45: SRS Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Self-diagnosis System

A self-diagnosis 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 (16P) (see GENERAL TROUBLESHOOTING INFORMATION ).

E-PRETENSIONER ('06-08 MODELS)

When at a risk of a collision, the e-pretensioner system, working with the collision mitigation braking
system (CMBS), retracts the driver's and front passenger's seat belt several times slightly to provide a tactile
warming to the driver. And when a collision is imminent, the e-pretensioner system retracts the seat belt
tightly to help reduce injury from the impact. The e-pretensioner system also works when the driver brakes
hard and the brake assist system is turned on.

CMBS AND E-PRETENSIONER OPERATION ('06-08 MODELS)

NOTE:

Before you disconnect the negative cable from the battery for
troubleshooting, make sure you have the anti-theft codes for the audio
system and the navigation system.

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2005-08 RESTRAINTS SRS (Supplemental Restraint System) - RL

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Approaching a vehicle ahead: When driving, the millimeter wave radar detects a vehicle ahead, and the
system provides audible and visual warnings if it detects a risk of collision.

Fig. 46: CMBS And E-pretensioner Operation ('06-08 Models) - Approaching Vehicle Ahead
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Closing on a vehicle ahead: The system applies light braking, and increases seat belt tension slightly to
provide a tactile warning to the driver. The front passenger does not feel the tactile warning.

Fig. 47: CMBS And E-pretensioner Operation ('06-08 Models) - Closing On Vehicle Ahead
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Collision unavoidable: The system activates strong braking, and securely tightens both the driver's and front
passenger's seat belts to help reduce injury caused by the impact.

Fig. 48: CMBS And E-pretensioner Operation ('06-08 Models) - Collision Unavoidable
Courtesy of AMERICAN HONDA MOTOR CO., INC.

E-PRETENSIONER ('06-08 MODELS)

The mechanical portion of the e-pretensioner consists of the motor and the gear sections. When the collision
mitigation brake or the brake assist system signals are input, the motor in the retractor section is driven to
rewind or retract. If the system judges that the driving situation is safe, the tension on the seat belts is
released. The e-pretensioners used in conjunction with the conventional tensioners.

2007 Acura RL

2005-08 RESTRAINTS SRS (Supplemental Restraint System) - RL

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