Signs Your Occupant Restraint Controller (ORC) Is Failing

The occupant restraint controller (ORC) is a key component of your car’s restraint system. The restraint system is very important to your safety in the event of a collision, so it is essential that your ORC is in good operating condition at all times. While every vehicle on the road with airbags has a device that functions like an ORC, this component may be identified by a different name in different brands of vehicles. These other names include:

• SRS (Supplemental Restraint System) Control Module
• Airbag ECU (Electronic Control Unit)
• Airbag Control Module (ACM)
• Restraint Control Module (RCM)
• Sensing Diagnostic Module (SDM)
• Sophisticated Airbag Sensor (SAS) Module

What the occupant restraint controller is and what it does

The occupant restraint controller is the computer brain that controls your car’s airbags and related systems. It can be located under one of the front seats, in the dashboard, or under the center console. The ORC is a very complex electronic system, with responsibility for many safety-related subsystems, including:

• Driver’s airbag
• Driver’s knee airbag
• Front passenger airbag
• Side-impact airbags (in front and rear seats)
• Side curtain airbags (in roof above side windows)
• Seat belt pre-tensioners
• Post-crash actions like shutting off fuel pump, unlocking doors, and activating 4-way flashers

The occupant restraint controller relies on a variety of sensors to provide it with information that a collision is about to happen. These sensors are located in the front of the vehicle to sense front-end crashes, as well as in the door beams, door pillars or rocker panels to sense side impacts.

By constantly monitoring the data being sent to it by these sensors, the ORC “decides” which airbag(s) should be inflated, and precisely when to inflate them.

The occupant restraint controller also stores information about any collision in which the airbags are deployed. The ORC records all the relevant accident-related data for the 20 seconds leading up to an impact. This can be used by technicians to repair and reset the system following the accident. The information may also be accessed by law enforcement and/or insurance carrier personnel to reconstruct the incident and determine the cause. This crash-related data can consist of:

• Vehicle speed
• Deceleration
• Throttle position
• Brake usage
• Seatbelt use

Each time that you start your car, the occupant restraint controller will run a self-diagnostic procedure to verify that all parts of the system are working properly, ready to protect you if needed. If a malfunction is detected in the system, a warning light will be illuminated. This is a signal to the driver that your airbag system has a problem that requires immediate attention. Do not delay in having this checked out – your airbags may not work in the event of an accident!

Symptoms of a bad occupant restraint controller

A problem with your occupant restraint controller will usually cause the airbag/SRS warning light on your dashboard to light up or flash. A trouble code may also be triggered. The fault will disable the airbag system until it is repaired. Possible causes within the ORC can include:

• A short circuit or other hardware fault within the occupant restraint controller
• Software fault in the ORC
• Damaged or shorted ORC wiring harness
• Bad electrical connection to the occupant restraint controller
• Physical damage to the ORC, possibly from a previous accident
• Water damage or corrosion in the occupant restraint controller

Repairing a bad occupant restraint controller

Because the occupant restraint controller is a complex electronic component full of integrated circuits and running its own software, a bad ORC will usually require replacement with a new one. Your mechanic (or body shop, if the ORC was damaged in an accident) will remove the damaged occupant restraint controller, replace it with a new one, and then reset it and test it for proper functioning in your vehicle.

Don’t try to repair a bad occupant restraint controller yourself

Unless you have had extensive experience in working with airbag systems, leave this one to the professionals! Your airbag system consists of several explosive devices, placed throughout your car’s interior. Your vehicle must be completely and properly powered down before any work begins, so that there is no possibility of an airbag firing during the repair procedure. Even experienced mechanics have been killed by exploding airbags during repair procedures. Specific diagnostic equipment is also required to troubleshoot the system. Leave the replacement of your occupant restraint controller to your repair shop and stay safe.