Part 1A

DESCRIPTION AND FUNCTIONAL OPERATION
The body electrical systems on the 2000 AB HIGH LINE consists of two modules that communicate over the CCD bus (Chrysler Collision Detection multiplex system). There are two additional modules, the Powertrain Control Module (PCM) and the Controller Anti-Lock Brake (CAB) that are not part of the body system, but do utilize the CCD bus for communication. The CAB also utilizes the bus for diagnostics. The PCM sends and receives messages on the CCD bus, however diagnostics are performed through the Serial Communication Interface of SCI, the same as previous years. All of the information about the functioning of all the system is organized, controlled, and communicated by the CCD bus, which is described in CCD Bus of this general information.

Through the CCD bus, information about the operation of vehicle components and circuits is relayed quickly to the appropriate module(s). All modules receive all the information transmitted on the bus even though a module may not require all the information to perform it's function. It will only respond to messages "addressed" to it through a binary coding process. This method of data transmission significantly reduces the complexity of the wiring in the vehicle and the size of wiring harnesses.

AIRBAG SYSTEM
The Airbag control Module (ACM) is secured to a bracket on the floor panel below the drivers seat. The ACM contains a microprocessor, the impact sensor, and energy storage capacitor. The microprocessor contains the airbag system logic. The ACM system logic includes On-Board Diagnostics (OBD) capability, and communicates with the instrument cluster circuitry on the Chrysler Collision Detection (CCD) data bus to control the airbag indicator lamp.

The microprocessor in the ACM monitors the impact sensor signal and the airbag system electrical circuits to determine the system readiness. If the ACM detects a monitored system fault, it sends messages to the instrument cluster on the CCD data bus to turn ON the airbag indicator lamp. A pre-programmed decision algorithm in the ACM microprocessor determines when the deceleration rate signaled by the impact sensor indicates an impact that is severe enough to require airbag system 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 an 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 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.

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 MUST 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. Whenever the ignition key is turned to the "run" or "start" position, the ACM performs a lamp check by turning the AIRBAG warning lamp ON for 6-8 seconds. If the lamp turns 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 MIC lamp circuit may be internally shorted to ground. If the lamp comes ON and stays ON for a period longer than 6-8 seconds then goes OFF, there is usually an intermittent problem in the system.

The MIC monitors the airbag warning lamp and seat belt warning lamp during the bulb check for a defective bulb or lamp driver circuit. The MIC tests the airbag lamp during the cluster bulb check and substitutes the seat belt lamp if the airbag lamp is defective. If the airbag lamp is defective the MIC will turn the seat belt light ON and OFF approximately 30 times to warn the driver that the airbag lamp is defective. The lamp status is sent to the ACM continuously via a CCD bus message. The seat belt lamp acts as a backup in the event that the AIRBAG lamp is defective. This information is sent to the ACM continuously via a CCD bus message.

Perform the WARNING LAMP BULB OR DRIVER procedure in this book 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.

Service and general information labels about the airbag system can be found on the driver's sun visor, the glove box door, and in the engine compartment.

WARNING: FAILURE TO HAVE THE AIRBAG SYSTEM PROPERLY SERVICED BY AN AUTHORIZED DEALER MAY LEAD TO POSSIBLE INJURY IN THE EVENT OF AN ACCIDENT.

Driver Airbag Module (DAB)
The airbag protection 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 are 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 a predetermined breakout line.

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 driver 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 Module (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 hold 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.

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 switch from the horizontal position to a slanted position (pointing to the "OFF" light indicator), approximately 45 degrees clockwise from the "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 in ON, this procedure will illuminate the "OFF" light indicator on the passenger airbag ON/OFF 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 KEY MUST ALWAYS BE REMOVED FROM THE PASSENGER AIRBAG ON/OFF SWITCH KEY CYLINDER AFTER THE SWITCH HAS BEEN USED. NEVER LEAVE A KEY IN THE ON/OFF KEY CYLINDER.

The ON/OFF switch cannot be adjusted or repaired and, if faulty or damaged, the ON/OFF switch must be replaced.

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). 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 PARTS CATALOG.

Airbag 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 DRBIII (R). 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.

The seat belt lamp replaces the airbag lamp if the airbag lamp is defective. The seat belt lamp pulses ON and OFF 30 times if the airbag warning lamp is defective.