Audible Warning Device Control Module: Description and Operation
CENTRAL TIMER MODULEThe Dakota (AN) and (AN84) utilize a Central Timer Module (CTM). This system is available in a Base or Highline configuration.
The CTM performs most of the typical functions a Body Control Module would perform.
Fig.1 Central Timer Module:
Two versions of the Central Timer Module (CTM) are available on this vehicle. Whichever version of the CTM the vehicle is equipped with, it is concealed behind the trim on the left cowl side inner panel below the instrument panel (Fig. 1). The base models are not equipped with the optional power lock system, the Remote Keyless Entry (RKE) system, the Vehicle Theft Security System (VTSS), or the remote radio controls. The high-line version of the CTM are used on vehicles that are equipped with one or more of those options.
The CTM utilizes circuitry, and information carried on the Programmable Communications Interface (PCI) data bus network, along with many hard wired inputs to monitor many sensor and switch inputs throughout the vehicle. In response to those inputs, the programming of the CTM allow it to supply the vehicle occupants with audible and visual information, and to control and integrate many electronic functions and features of the vehicle through both hard wired outputs and the transmission of electronic message outputs to other electronic modules in the vehicle over the PCI data bus.
The Base and Highline CTM supports or controls the following features:
- Automatic Door Lock
- Battery Saver Functions For Exterior and Interior Lamps
- Cargo Lamps
- Chime Warning
- Courtesy Lamps
- Dome Lamps
- Dome Defeat
- Door Ajar Switch Status
- Fog Lamps
- Head Lamp Time Delay
- Low and High Beam Head Lamps
- Optical Horn
- Park Lamps
- Speed Sensitive Intermittent Wiper Controls
Additional features of Highline CTM
- Central Locking (VTSS)
- Door Lock Inhibit
- Driver Door Unlock
- Enhanced Accident Response
- Horn Chirp
- Optical Chirp
- Panic Mode
- Power Door Locks
- Programmable Features
- Remote Keyless Entry
- Remote Radio Switch Interface
- Vehicle Theft Security System (VTSS)
The high-line Central Timer Module (CTM) can also control some features of the audio system when the vehicle is equipped with the optional remote radio switches. A high-line CTM is used on high-line versions of this vehicle. The CTM combines the functions of a chime/buzzer module, an intermittent wipe module, an illuminated entry module, a remote keyless entry module, and a vehicle theft security system module in a single unit.
The high-line CTM also controls and integrates many of the additional electronic functions and features included on models with this option. The RAZ radio receiver with a remote radio switch option is one of the features that the CTM controls. The CTM is programmed to send switch status messages over the Programmable Communications Interface (PCI) data bus to control the volume, seek, and pre-set station advance functions of the optional radio receiver. The CTM monitors the status of the remote radio switches located on the steering wheel through a hard wired circuit. The CTM then sends the proper switch status messages to the radio receiver. The electronic circuitry within the radio receiver responds to the switch status messages it receives by adjusting the radio settings as requested.
(Refer to BODY CONTROL/CENTRAL TIMER MODULE - DESCRIPTION) for more information on the high-line CTM. (Refer to REMOTE SWITCHES DESCRIPTION) for more information on this component. In addition, radio receivers connected to the PCI data bus have several audio system functions that can be diagnosed using a DRB scan tool. Refer to the proper Diagnostic Procedures for more information on DRB III testing of the audio systems.
Hard wired circuitry connects the CTM to the electrical system of the vehicle. Refer to the appropriate wiring information.
All versions of the CTM for this model are serviced only as a complete unit. Many of the features in the vehicle controlled or supported by the CTM are programmable using the DRB III scan tool. If any of the CTM hardware components are damaged or faulty the entire CTM unit must be replaced. The hard wired inputs or outputs of all CTM versions can be diagnosed using conventional diagnostic tools and methods. For diagnosis of the CTM or the PCI data bus, the use of a DRB III scan tool is required. Refer to the appropriate diagnostic information.
The Central Timer Module (CTM) monitors many hard wired switch and sensor inputs as well as those resources it shares with other modules in the vehicle through its communication over the Programmable Communications Interface (PCI) data bus network. The programming and all of the inputs allow the CTM to determine the tasks it needs to perform and their priorities, as well as both the standard and optional features that it should provide. The CTM then performs those tasks and provides those features through both PCI data bus communication with other modules and through hard wired outputs through a number of driver circuits, relays, and actuators. These outputs allow the CTM the ability to control numerous accessory systems.
The CTM operates on battery voltage received through two fuses in the Junction Block (JB) on two non-switched fused B(+) circuits, a fused ignition switch output (RUN/START) circuit, and a fused ignition switch output (RUN/ACC) circuit. This arrangement allows the CTM to provide some features regardless of the ignition switch position. The CTM is grounded to the chassis. Two of these ground circuits are on the left inner cowl panel near the CTM, while the third is near the Airbag Control Module (ACM).
The CTM monitors its own internal circuitry as well as many of its input and output circuits, and will store Diagnostic Trouble Codes (DTC) in memory for any failure it detects. These DTCs can be retrieved and diagnosed using a DRB III scan tool. Refer to the appropriate diagnostic information.
Hard Wired Inputs
The hard wired inputs to the CTM include the following:
- Cargo lamp switch sense
- Courtesy lamp switch sense
- Cylinder lock switch sense - high line with VTSS only
- Driver door ajar switch sense
- Driver door switch MUX - high line with power locks only
- Fog lamp switch sense
- Front washer pump/motor control
- Front wiper park switch sense
- Fused B(+) (two circuits)
- Fused ignition switch output (RUN/ACC)
- Fused ignition switch output (RUN/START)
- Ground (three circuits)
- Headlamp switch off sense
- High beam switch output
- Interior lamp defeat
- Intermittent front wiper mode sense
- Intermittent front wiper switch signal
- Key-in ignition switch sense
- Low beam switch output
- Park brake switch sense
- Park lamp switch sense
- Passenger door ajar switch sense
- Passenger door switch MUX - high line with power locks only
- PCI bus circuit
- Radio control MUX - high-line with remote radio switches only
- Washer switch sense
- Wiper park switch sense
- Wiper switch mode sense
- Wiper switch mode signal
Hard Wired Outputs
The hard wired outputs of the CTM include the following:
- Cargo lamp driver
- Courtesy lamp driver
- Door lock relay output - high-line with power locks only
- Door unlock relay output - high-line with power locks only
- Driver door unlock relay output
- Fog lamp relay control - with fog lamps only
- Front washer pump/motor control
- Front wiper park switch sense
- Front wiper relay control
- Glove box lamp driver
- High beam indicator driver
- Horn relay control - high-line with power locks only
- Interior lamp driver
- Left high beam driver
- Left low beam driver
- Park lamp relay control
- Right high beam driver
- Right low beam driver
- VTSS indicator driver - high-line with VTSS only
Messaging
The CTM uses the following messages received from other modules over the PCI data bus:
- Airbag Deploy (ACM)
- Beep request (CMTC)
- Charging System Failure (PCM)
- Chime request (EMIC)
- Engine RPM (PCM)
- OK to Arm VTSS (PCM)
- Security indicator request (SKIM)
- System Voltage (PCM)
- Valid/Invalid Key (SKIM)
- Vehicle Distance (PCM)
- Vehicle Speed (PCM)
- Voltage Fault (PCM)
The CTM provides the following messages to other electronic modules over the PCI data bus:
- Door Ajar Status (EMIC)
- Park Brake Status (CAB, EMIC, TCM)
- Radio Mode (Radio)
- Radio Preset Scan (Radio)
- Radio Seek Down (Radio)
- Radio Seek Up (Radio)
- Radio Volume Down (Radio)
- Radio Volume Up (Radio)
- Ignition Staus
- VTSS Status
- Country Code