Dodge Nitro. Manual - part 227

Front Impact Sensor (1) - Two front impact sensors are used on vehicles equipped with dual front 
airbags, one left side and one right side. One sensor is located on the back side of the front end module 
carrier on either side of the radiator and inboard of the headlamp within the engine compartment.  

Occupant Classification Module (6) - Vehicles equipped with the Occupant Classification System 
(OCS) include an Occupant Classification Module (OCM) which is secured to a bracket on the inboard 
side of the inboard passenger side seat track riser beneath the seat cushion.  

Occupant Restraint Controller (8) - The Occupant Restraint Controller (ORC) is located on a mount on 
the floor panel transmission tunnel rearward of the transmission gear selector, and is concealed beneath 
the center floor console.  

Passenger Airbag (2) - The passenger airbag is located in the instrument panel, beneath the passenger 
airbag door on the instrument panel above the glove box on the passenger side of the vehicle.  

Passenger Airbag On/Off Indicator (3) - Vehicles with the Occupant Classification System (OCS) 
include a passenger airbag on/off indicator which is located in the instrument panel switch pod near the 
base of the instrument panel lower center bezel.  

Passenger Knee Blocker - The passenger knee blocker is a structural reinforcement that is integral to and 
concealed within the glove box door.  

Seat Belt Tensioner (9 and 10) - Dual seat belt tensioners are integral to both front seat belt buckle units 
(9) and retractor units (10) on vehicles equipped with dual front airbags. The seat belt buckle tensioner 
units are located on the inboard rear corner of each front seat cushion. The seat belt retractor tensioner 
units are secured to the right and left inner B-pillars and concealed beneath the lower B-pillar trim.  

Seat Weight Sensor (5) - Vehicles equipped with the Occupant Classification System (OCS) include four 
seat weight sensors, one on each corner of the passenger side front seat between the lower seat adjuster 
tracks and the seat track risers.  

Side Curtain Airbag (12) - A side curtain airbag is secured to each inside roof side rail above the 
headliner, and extends from the A-pillar to just beyond the C-pillar.  

Side Impact Sensor (11) - Four side impact sensors are used on vehicles equipped with side curtain 
airbags, two left side and two right side. One sensor is located behind the trim above the front seat belt 
retractor on each inner B-pillar and one is located above the second row outboard retractor on each inner 
C-pillar.  

The ORC, the OCM, and the EMIC each contain a microprocessor and programming that allow them to 
communicate with each other using the Controller Area Network (CAN) data bus. This method of 
communication is used by the ORC for control of the airbag indicator in the EMIC. Refer to DESCRIPTION . 

Hard wired circuitry connects the SRS components to each other through the electrical system of the vehicle. 
These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and 
retained by many different methods. These circuits may be connected to each other, to the vehicle electrical 
system, and to the SRS components through the use of a combination of soldered splices, splice block 
connectors, and many different types of wire harness terminal connectors and insulators. Refer to the 
appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector 
repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for 
the various wire harness connectors, splices and grounds. 

OPERATION 

 

2007 Dodge Nitro R/T 

2007 RESTRAINTS Service Information - Nitro

  

RESTRAINT SYSTEM 

ACTIVE RESTRAINTS 

The primary passenger restraints in this or any other vehicle are the standard equipment factory-installed seat 
belts and child restraint anchors. Seat belts and child restraint anchors are referred to as an active restraint 
because the vehicle occupants are required to physically fasten and properly adjust these restraints in order to 
benefit from them. 

PASSIVE RESTRAINTS 

The passive restraints are referred to as a Supplemental Restraint System (SRS) because they were designed and 
are intended to enhance the protection for the occupants of the vehicle only when used in conjunction with the 
seat belts. They are referred to as passive restraints because the vehicle occupants are not required to do 
anything to make them operate; however, the vehicle occupants must be wearing their seat belts in order to 
obtain the maximum safety benefit from the factory-installed SRS components. 

The SRS electrical circuits are continuously monitored and controlled by a microprocessor and software 
contained within the Occupant Restraint Controller (ORC). An airbag indicator in the Electro Mechanical 
Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) illuminates for about seven 
seconds as a bulb test each time the ignition switch is turned to the ON or START positions. Following the bulb 
test, the airbag indicator is turned ON or OFF by the ORC to indicate the status of the SRS. If the airbag 
indicator comes ON at any time other than during the bulb test, it indicates that there is a problem in the SRS 
electrical circuits. Such a problem may cause airbags not to deploy when required, or to deploy when not 
required. 

Deployment of the SRS components depends upon the angle and severity of an impact. Deployment is not 
based upon vehicle speed; rather, deployment is based upon the rate of deceleration as measured by the forces 
of gravity (G force) upon the acceleration-type impact sensors. When an impact is severe enough, the 
microprocessor in the ORC signals the inflator of the appropriate airbag units to deploy their airbag cushions. 
The front seat belt retractor tensioners and, if equipped, buckle tensioners are provided with a deployment 
signal by the ORC in conjunction with the front or side curtain airbags. The side curtain airbags are provided 
with a deployment signal individually by the ORC based upon a side impact sensor input for the same side of 
the vehicle. 

During a frontal vehicle impact, the knee blockers work in concert with properly fastened and adjusted seat 
belts to restrain both the driver and the front seat passenger in the proper position for an airbag deployment. The 
knee blockers also absorb and distribute the crash energy from the driver and the front seat passenger to the 
structure of the instrument panel. The seat belt tensioners remove the slack from the front seat belts to provide 
further assurance that the driver and front seat passenger are properly positioned and restrained for an airbag 
deployment. 

Typically, the vehicle occupants recall more about the events preceding and following a collision than they do 
of an airbag deployment itself. This is because the airbag deployment and deflation occur very rapidly. In a 
typical 48 kilometer-per-hour (30 mile-per-hour) barrier impact, from the moment of impact until the airbags 
are fully inflated takes about 40 milliseconds. Within one to two seconds from the moment of impact, the 
airbags are almost entirely deflated. The times cited for these events are approximations, which apply only to a 
barrier impact at the given speed. Actual times will vary somewhat, depending upon the vehicle speed, impact 

 

2007 Dodge Nitro R/T 

2007 RESTRAINTS Service Information - Nitro

  

angle, severity of the impact, and the type of collision.

When the ORC monitors a problem in any of the SRS circuits or components, including the seat belt tensioners, 
it stores a fault code or Diagnostic Trouble Code (DTC) in its memory circuit and sends an electronic message 
to the EMIC to turn ON the airbag indicator. The hard wired circuits between components related to the SRS 
may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring 
information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, 
details of wire harness routing and retention, connector pin-out information and location views for the various 
wire harness connectors, splices and grounds. 

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the SRS or the 
electronic controls or communication between other modules and devices that provide features of the SRS. The 
most reliable, efficient, and accurate means to diagnose the SRS or the electronic controls and communication 
related to SRS operation, as well as the retrieval or erasure of a DTC requires the use of a diagnostic scan tool. 
Refer to the appropriate diagnostic information. 

OCCUPANT CLASSIFICATION SYSTEM 

In vehicles equipped with the Occupant Classification System (OCS), the OCS automatically suppresses or 
enables passenger airbag and seat belt tensioner operation based upon whether or not the passenger side front 
seat is occupied and, if the seat is occupied, classifies the size of the occupant and whether the seat is occupied 
by a child seat. The passenger airbag and seat belt tensioners are disabled when the system senses the seat is 
occupied by a child seat or a person below a minimum weight threshold. 

The OCS has an Occupant Classification Module (OCM) that monitors inputs from the seat weight sensors 
under the passenger side front seat cushion. Based upon those inputs the microprocessor within the OCM 
classifies the occupant of the passenger side front seat. The OCM then sends electronic occupant classification 
messages to the Occupant Restraint Controller (ORC). The microprocessor and programming of the ORC 
determines whether to enable or disable the deployment circuits for the passenger airbag and seat belt 
tensioners; and, if enabled, what force level should be used to deploy each front airbag. 

The OCS electrical circuits and components are continuously monitored by the OCM, and the OCM is 
continuously monitored by the ORC. A passenger airbag on/off indicator is located in the instrument panel 
switch pod near the base of the instrument panel center bezel. This indicator receives battery current whenever 
the ignition switch is in the ON or START positions, and illuminates only when the ORC pulls the indicator 
control circuit to ground. The indicator illuminates for about seven seconds as a bulb test each time the ignition 
switch is turned to the ON or START positions. Following the bulb test, the indicator is turned ON or OFF by 
the ORC based upon the electronic occupant classification messages received from the OCM. This indicator is 
illuminated whenever the seat is occupied and passenger airbag and seat belt tensioner operation has been 
suppressed. The indicator is turned OFF whenever the seat is empty or when the seat is occupied and the 
passenger airbag and seat belt tensioners are enabled. 

When the OCM monitors a problem in any of the OCS circuits or components, it stores a fault code or DTC in 
its memory circuit and sends an electronic message to the ORC. The ORC then sends an electronic message to 
the Electro Mechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) to turn 
ON the airbag indicator. If for any reason the OCM is unable to classify the occupant it sends an electronic 
message to the ORC, and the ORC suppresses passenger airbag and seat belt tensioner operation. The hard 
wired circuits between components related to the OCS may be diagnosed using conventional diagnostic tools 

 

2007 Dodge Nitro R/T 

2007 RESTRAINTS Service Information - Nitro

  

and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, 
proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out 
information and location views for the various wire harness connectors, splices and grounds. 

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the OCS or the 
electronic controls or communication between other modules and devices that provide features of the OCS. The 
most reliable, efficient, and accurate means to diagnose the OCS or the electronic controls or communication 
related to OCS operation, as well as the retrieval or erasure of a DTC requires the use of a diagnostic scan tool. 
Refer to the appropriate diagnostic information. 

WARNING 

RESTRAINT SYSTEM 

WARNING:

To avoid serious or fatal injury during and following any seat belt or child 
restraint anchor service, carefully inspect all seat belts, buckles, 
mounting hardware, retractors, tether straps, and anchors for proper 
installation, operation, or damage. Replace any belt that is cut, frayed, or 
torn. Straighten any belt that is twisted. Tighten any loose fasteners. 
Replace any belt that has a damaged or ineffective buckle or retractor. 
Replace any belt that has a bent or damaged latch plate or anchor plate. 
Replace any child restraint anchor or the unit to which the anchor is 
integral that has been bent or damaged. Never attempt to repair a seat 
belt or child restraint component. Always replace damaged or ineffective 
seat belt and child restraint components with the correct, new and 
unused replacement parts 

WARNING:

To avoid serious or fatal injury on vehicles equipped with side curtain 
airbags, disable the supplemental restraint system before attempting any 
occupant restraint controller diagnosis or service. The occupant restraint 
controller contains a rollover sensor, which enables the system to deploy 
the side curtain airbags in the event of a vehicle rollover event. If an 
occupant restraint controller is accidentally rolled during service while 
still connected to battery power, the side curtain airbags will deploy. 
Disconnect and isolate the battery negative (ground) cable, then wait two 
minutes for the system capacitor to discharge before performing further 
diagnosis or service. This is the only sure way to disable the 
supplemental restraint system. Failure to take the proper precautions 
could result in accidental airbag deployment.

WARNING:

To avoid serious or fatal injury on vehicles equipped with airbags, disable 
the supplemental restraint system before attempting any steering wheel, 
steering column, airbag, occupant classification system, seat belt 
tensioner, impact sensor, or instrument panel component diagnosis or 
service. Disconnect and isolate the battery negative (ground) cable, then 
wait two minutes for the system capacitor to discharge before performing 

 

2007 Dodge Nitro R/T 

2007 RESTRAINTS Service Information - Nitro