Airbag System
AIRBAG SYSTEMThe driver and passenger airbag system is a safety device designed to reduce the risk of fatality or serious injury, caused by a frontal impact of the vehicle.
The Airbag Control Module (ACM) contains the impact sensor and energy reserve capacitor. The ACM monitors the system to determine the system readiness. The ACM contains on-board diagnostics and will light the AIRBAG warning lamp in the message center when a problem occurs.
The impact sensor provides verification of the direction and severity of the impact. One impact sensor is used. It is located inside the Airbag Control Module (ACM) which is mounted on a bracket, behind the instrument panel center bezel, underneath the radio. The impact sensor is an accelerometer that senses deceleration. The deceleration pulses are sent to a microprocessor which contains a decision algorithm. When an impact is severe enough to require airbag protection, the ACM microprocessor sends a signal that completes the electrical circuit to the driver and passenger airbags. The sensor is calibrated for the specific vehicle and reacts to the severity and direction of the impact.
The Airbag Control Module (ACM) is secured to a bracket on the floor panel transmission tunnel below the instrument panel inside the vehicle. The ACM mounting bracket also serves as the instrument panel center support. The ACM's microprocessor determines when the deceleration rate signaled by the impact sensor indicates that the impact is severe enough to require airbag protection. When the programmed conditions are met, the ACM sends an electrical signal to deploy the airbag system components.
Only one impact sensor is used in this airbag system. The impact sensor is an accelerometer that senses the rate of vehicle deceleration, which provides verification of the direction and severity of the impact. The impact sensor is calibrated for the specific vehicle, and is only serviced as a unit with the ACM.
The ACM also contains an energy storage capacitor. This capacitor stores enough electrical energy to deploy the airbags, for one second following a battery disconnect or failure during an impact. The purpose of the capacitor is to provide the airbag system protection in a severe secondary impact if the initial impact has damaged or disconnected the battery, but was not severe enough to deploy the airbags.
WARNING THE AIRBAG SYSTEM IS A SENSITIVE, COMPLEX ELECTROMECHANICAL UNIT. BEFORE ATTEMPTING TO DIAGNOSE OR SERVICE ANY AIRBAG SYSTEM OR RELATED STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENTS YOU MUST FIRST DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE. THEN WAIT TWO MINUTES FOR THE SYSTEM CAPACITOR TO DISCHARGE BEFORE FURTHER SYSTEM SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO DO THIS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.
Never strike or kick the airbag control module, as it can damage the impact sensor or affect its calibration. If an airbag control module is accidentally dropped during service, the module has to be scrapped and replaced with a new unit.
The airbag warning lamp is the only point at which the customer can observe "symptoms" of a system malfunction. The warning lamp is hard-wired to the ACM. Whenever the ignition key is turned to the "start" or "run" position, the ACM performs a lamp check by turning the AIRBAG warning lamp on for 6 to 8 seconds. If the lamp remains OFF, it means that the ACM has checked the system and found it to be free of discernible malfunctions. If the lamp remains on, there could be an active fault in the system or the message center lamp circuit may be internally shorted to ground. If the lamp comes on and stays on for a period longer than 6 to 8 seconds than goes OFF, there is usually in intermittent problem in the system.
Perform the WARNING LAMP OPEN/SHORTED procedure to find the cause of any customer complaint regarding the airbag warning lamp, such as:
* warning lamp does not illuminate
* warning lamp stays illuminated with no active DTC's
The ACM cannot be repaired or adjusted and, if damaged or faulty, it must be replaced.
DRIVER AIRBAG (DAB)
The airbag protective trim cover is the most visible part of the driver side airbag system. The module is mounted directly to the steering wheel. Located under the trim cover of the horn switch, the airbag cushion, and the airbag cushion supporting components. The airbag module includes a housing to which the cushion and inflator are attached and sealed. The airbag module cannot be repaired, and must be replaced if deployed or in any way damaged. The inflator assembly is mounted to the back of the airbag module. The inflator seals the hole in the airbag cushion so it can discharge the gas it produces directly into the cushion when supplied with the proper electrical signal. The protective trim cover is fitted to the front of the airbag module and forms a decorative cover in the center of the steering wheel. Upon airbag deployment, this cover will split at predetermined breakout line.
CAUTION: The airbag module inflator assembly contains sodium azide and potassium nitrate. These materials are poisonous and extremely flammable. Contact with acid, water or heavy metals may produce harmful and irritating gases (sodium hydroxide is formed in the presence of moisture) or combustible compounds. In addition, the passenger airbag module contains argon gas pressurized to over 2500 PSI. Do not attempt to dismantle an airbag module or tamper with its inflator. Do not puncture, incinerate, or bring into contact with electricity. Do not store at temperature exceeding 93° C (200° F).
CLOCKSPRING
The clockspring is mounted on the steering column behind the steering wheel. This assembly consists of a plastic housing which contains a flat, ribbon-like, electrically conductive tape that winds and unwinds with the steering wheel rotation. The clockspring is used to maintain a continuous electrical circuit between the instrument panel wire harness and the drive side airbag module, the horn switch, and the vehicle speed control switches on vehicles that are so equipped. The clockspring must be properly centered when it is installed on the steering column following any service removal, or it will be damaged.
The clockspring cannot be repaired it must be replaced.
PASSENGER AIRBAG (PAB)
The airbag door in the instrument panel top cover above the glove box is the most visible part of the passenger side airbag system. Located under the airbag door is the airbag cushion and it's supporting components. The airbag module includes a housing to which the cushion and inflator are attached and sealed. The airbag module cannot be repaired, and must be replaced if deployed or in any way damaged. The inflator assembly is mounted to the back of the airbag module. The inflator includes a small canister of highly compressed argon gas. The inflator seals the hole in the airbag cushion so it can discharge the compressed gas it contains directly into the cushion when supplied with the proper electrical signal. The airbag door has a living hinge at the top, which is secured to the instrument panel top cover. The door also has predetermined breakout lines concealed beneath its decorative cover. Upon airbag deployment, the airbag door will split at the breakout lines and the door will pivot out of the way.
The airbag module is secured at the bottom to the steel structural base of the instrument panel above the glove box opening. The airbag door is serviced as a unit with the passenger side airbag module, and includes the two passenger heating and air conditioning panel outlet housings. Following an airbag deployment, the airbag module and the instrument panel assembly must be replaced.
CAUTION: The airbag module inflator assembly contains sodium azide and potassium nitrate. These materials are poisonous and extremely flammable. Contact with acid, water or heavy metals may produce harmful and irritating gases (sodium hydroxide is formed in the presence of moisture) or combustible compounds. In addition, the passenger airbag module contains argon gas pressurized to over 2500 PSI. Do not attempt to dismantle an airbag module or tamper with it's inflator. Do not puncture, incinerate, or bring into contact with electricity. Do not store at temperature exceeding 93° C (200° F).
Replace airbag system components only with parts specified in the Chrysler Mopar Parts Catalog. Substitute parts may appear interchangeable, but internal differences may result in inferior occupant protection. The fasteners, screws, and bolts originally used for the airbag system components have special coatings and are specifically designed for the airbag system. They must never be replaced with any substitutes. Any time a new fastener is needed, replace it with the correct fasteners provided in the service package or specified in the Chrysler Mopar Parts Catalog.
PASSENGER AIRBAG ON-OFF SWITCH
The passenger side airbag ON-OFF switch is located on the instrument panel. To de-activate the passenger side airbag, turn the key actuator from the horizontal position to a slant position (pointing to the "OFF" light indicator), approximately 45 degrees clockwise from the Passenger Airbag On/Off Switch "On" position. Rotating the key actuator switch 45 degrees clockwise, remove the key completely from the switch and verify that the switch actuator hole stays in the new position (45 degrees clockwise from horizontal). The switch is spring loaded to the "on" position. It will return to the "on" position unless you remove the key. When the ignition is ON, this procedure will illuminate the "OFF" light indicator on the passenger airbag disable switch.
To re-enable the passenger side airbag, reverse the procedure above so that the key switch actuator is returned to a horizontal position.
NOTE: Do not turn ignition ON with key in switch. Do not turn switch with ignition ON. Do not leave key in switch.
The Passenger Airbag ON-OFF Switch cannot be adjusted or repaired and, if faulty or damaged, the Passenger Airbag ON-OFF Switch must be replaced.
Special Tools
Some airbag diagnostic test use special tools, 8310 and 8443 airbag load tool, for testing squib circuits.
The load tools contain fixed resistive loads, jumpers and adapters. The fixed loads are connected to cables and mounted in a storage case. The cables can be directly connected to some airbag system connectors. Jumpers are used to convert the load tool cable connectors to the other airbag system connectors.
The adapters are connected to the module harness connector to open shorting clips and protect the connector terminal during testing. When using the load tool follow all of the safety procedures in the service information for disconnecting airbag system components
Inspect the wiring, connector and terminals for damage or misalignment.
Substitute the airbag load tool in place of a Driver or Passenger Airbag, clockspring, (use a jumper if needed). Then follow all of the safety procedures in the service information for connecting airbag system components.
Read the module active DTC's. If the module reports NO ACTIVE DTC's the defective component has been removed from the system and should be replaced. If the DTC is still active, continue this process until all components in the circuit have been tested. Then disconnect the module connector and connect the matching adapter to the module connector. With all airbags disconnected and the adapter installed the squib wiring can be tested for open and shorted conditions.
Diagnostic Trouble Codes
Airbag diagnostic trouble codes consist of active and stored codes. If more than one code exists, diagnostic priority should be given to the active codes.
Each diagnostic trouble code is diagnosed by following a specific testing procedure. The diagnostic test procedures contain step-by-step instructions for determining the cause of the trouble codes. It is not necessary to perform all of the tests in this book to diagnose an individual code.
Always begin by reading the diagnostic trouble codes using the DRB. This will direct you to the specific test(s) that must be performed.
Active diagnostic trouble codes for the airbag system are not permanent and will change the moment the reason for the code is corrected. In certain test procedures, diagnostic trouble codes are used as a diagnostic tool.
Active Codes
The code becomes active as soon as the malfunction is detected or key OFF, whichever occurs first. An active trouble code indicates an on-going malfunction. This means that the defect is currently there every time the airbag control module checks that circuit/function. It is impossible to erase an active code; active codes automatically erase by themselves when the reason for the code has been corrected.
With the exception of the warning lamp trouble codes or malfunctions, when a malfunction is detected, the airbag lamp remains lit for a minimum of 12 seconds or as long as the malfunction is present.
Stored Codes
Airbag codes are automatically stored in the ACM's memory as soon as the malfunction is detected. The exception is the "Loss of Ignition Run Only" code which is an active code only.
A "stored" code indicates there was an active code present at some time.
When a trouble code occurs, the airbag warning lamp illuminates for 12 seconds minimum (even if the problem existed for less than 12 seconds). The code is stored, along with the time in minutes it was active, and the number of times the ignition has been cycled since the problem was last detected.
The minimum time shown for any code will be one minute, even if the code was actually present for less than one minute. Thus, the time shown for a code that was present for two minutes 13 seconds, for example, would be three minutes.
If a malfunction is detected a diagnostic trouble code is stored and will remain stored as long as the malfunction exists. When and if the malfunction ceases to exist, an ignition cycle count will be initiated for that code. If the ignition cycle count reaches 100 without a reccurrence of the same malfunction, the diagnostic trouble code is erased and that ignition cycle counter is reset to zero. If the malfunction reoccurs before the count reaches 100, then the ignition cycle counter will be reset and the diagnostic trouble code will continue to be a stored code.
If a malfunction is not active while performing a diagnostic test procedure, the active code diagnostic test will not locate the source of the problem. In this case, the stored code can indicate an area to inspect.
Maintain a safe distance from all airbags while performing the following inspection. If no obvious problems are found, erase stored codes, and with the ignition "on" wiggle the wire harness and connectors, rotate the steering wheel from stop to stop. Recheck for codes periodically as you work through the system. This procedure may uncover a malfunction that is difficult to locate.