CCD BUS SYSTEM
The Chrysler Collision Detection (CCD) bus is a pair of twisted wires traveling from module-to-module receiving and delivering coded information. The code identifies the message and its importance. When multiple messages attempt to access CCD bus at once, code assigns priority ranking.
The 2 twisted wires used by the CCD bus system are called bus "+" (positive) and bus "-" (negative). Both wires carry approximately 2.5 volts. The network consists of some modules with "bias" and some with "termination".
Bias is the part of the voltage divider network which places both bus "+" and bus "-" at 2.5 volts. Termination is the part of the circuitry required to complete the voltage divider network and also provide some electromagnetic protection for the CCD bus. Terminations in all CCD applications have approximately 120 ohms resistance.
CENTRAL TIMER MODULE
The Central Timer Module (CTM) high line model only communicates over CCD bus line. CTM controls air bag, chime, courtesy lights, illuminated entry, power door locks, remote keyless entry, speed sensitive intermittent wipers and vehicle theft security system. For module location, see CTM MODULE LOCATION table.
| Model | Location |
|---|---|
| Dakota & Durango | Right Side Of Glove Box, Behind Metal Bracket |
| Ram Pickup | Right Side Of Steering Column, Behind Knee Bolster |
| Ram Van & Ram Wagon | Left Center Instrument Panel Support |
CTM MODULE LOCATION
COMPASS/MINI-TRIP COMPUTER (CMTC)
The CMTC is located in overhead console. This dual-function display provides a digital readout of ambient (outside) temperature and 8 primary compass readings to indicate the direction in which vehicle is facing.
The CMTC is self-calibrated and requires no adjustment. The word CAL will be displayed to indicate that the compass is in the fast calibrating mode. The CAL display may be turned off after the vehicle has completed 3 circles without stopping, in an area free of magnetic disturbance.
If the module displays ambient temperature while the compass display is blank, the vehicle must be demagnetized. If compass display still goes blank after the vehicle is demagnetized, the compass/temperature module must be replaced.
MECHANICAL INSTRUMENT CLUSTER (MIC)
Instrument cluster includes a speedometer, tachometer, fuel gauge, oil pressure gauge, water temperature gauge, voltmeter, Vacuum Fluorescent (VF) display and a series of warning lights.
Powertrain Control Module (PCM) sends signals necessary for the cluster to position gauges. Cluster receives these messages from CCD or PCI bus and translates them into gauge positions. BCM sends status of all indicator lights and dimming level to instrument cluster over CCD or PCI bus when ignition switch is in RUN or START positions. Malfunction (CHECK ENGINE) indicator light status is sent to BCM from PCM over CCD or PCI bus. Vacuum fluorescent odometer/trip display works when ignition switch is in RUN or START positions. BCM stores mileage information that odometer displays. If CCD bus is not functioning, odometer will display dashes instead of the mileage numbers. BCM sends mileage message and dimming level message to vacuum fluorescent display when ignition switch is in the ON position. All other instrument cluster features only work when the ignition switch is in the RUN position.
MEMORY HEATED SEAT & MIRROR SYSTEM
The Memory Heated Seat/Mirror Module (MHSMM) mounted under driver's seat, reads all seat switch, mirror switch and radio station preset inputs programmed by driver. Functionality includes memory preset capabilty for a second driver. Two stored sets of preferences can be recalled upon request.
The MHSMM monitors memory switches and stores desired positions in memory. MHSMM will activate seat and mirror motors in response to a recall request from individual memory switch or Remote Keyless Entry (RKE) fob.
OVERHEAD TRAVEL INFORMATION SYSTEM (OTIS)
The OTIS provides vehicle operator with supplementary information on a Vacuum Fluorescent (VF) display. The OTIS is located in overhead console. Vehicle operator selects and resets display functions through the use of 4 buttons (US/M, STEP, C/T and RESET). The OTIS obtains most of its information from the CCD or PCI bus.
The OTIS powers up when it senses vehicle (battery) voltage on the ignition input circuit. The OTIS blanks the display, then illuminates all segments of the VF display. During this time, the OTIS sends and receives information over CCD or PCI bus to determine what to display after its 2 second initialization. OTIS will display dashes (- -) for any of the screens for which it did not receive bus messages during the 2 second initialization. Dashes will be replaced by valid information if and when it is received.
PCI BUS SYSTEM (CONCORDE, INTREPID, LHS & 300M)
The Programmable Communication Interface multiplex system (PCI bus) consists of a single wire. The BCM acts as a splice to connect each module and DLC. Each module uses its local ground as bus reference. If more than one module is trying to access the PCI bus at one time, the code being sent determines which message has higher priority, and is then allowed to access bus first. Communication over the bus is essential to proper operation of vehicles on-board diagnostic systems and DRB. Problems with operation of bus or DRB must be corrected before proceeding with diagnostic testing. See appropriate VEHICLE COMMUNICATIONS article.
VEHICLE THEFT SECURITY SYSTEM (VTSS)
VTSS monitors vehicle doors, hood, trunk key cylinder and ignition for unauthorized operation/entry. When alarm is triggered, the horn will sound for 3 minutes and the parking lights will flash for 15-18 minutes.
When an unauthorized entry into vehicle occurs, the VTSS module signals Powertrain Control Module (PCM) via CCD or PCI bus that it is not okay to start the engine. The PCM then "zeros out" the pulse width of the fuel injectors, thus preventing the engine from starting (start/stall condition). The engine will NOT start until VTSS is disarmed.
Initialization & Verification
An initialization procedure, included in VTSS requires that vehicle record 20 engine cranking cycles before allowing VTSS module to function. For this reason, VTSS requires verification. To verify VTSS, perform the following: Open driver's door (all others closed). Remove ignition key. Lock doors with power door lock switch. Close driver's door. If VTSS SET light flashes, system is armed and operational. If VTSS SET light does not flash, 20 engine cranking cycles have not occurred or there is a problem with VTSS.
Manual Override Mode & Tamper Alert Mode
The VTSS will not arm if the doors are locked using the key or the manual lock control (manual override mode). If horn sounds 3 times when either front door is unlocked, the alarm was activated/triggered (tamper alert mode).