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Body Control Module: Description and Operation

SYSTEM OPERATION
Central Timer Module
Two versions of the Central Timer Module (CTM) are available on this vehicle, a base version and a high-line version. The base version of the CTM is used on base models of the vehicle. The base version of the CTM combines the functions of a chime/buzzer module, an intermittent wipe module, and an ignition lamp time delay relay in a single unit.

The high-line version of the CTM is used on high-line vehicles. The high-line CTM provides all of the functions of the base version CTM, but also is used to control and integrate many of the additional electronic functions and features included on the high-line models. The high-line version of the CTM contains a central processing unit and interfaces with other modules in the vehicle on the Chrysler Collision Detection (CCD) data bus network.

The CCD data bus network allows the sharing of sensor information. This helps to reduce wire harness complexity, reduce internal controller hardware, and reduce component sensor current loads. At the same time, this system provides increased reliability, enhanced diagnostics, and allows the addition of many new feature capabilities.

The horn relay is one of the outputs that the high-line CTM can control. The high-line CTM is programmed to energize or de-energize the horn relay in response to certain inputs from the Vehicle Theft Security System (VTSS) and the Remote Keyless Entry (RKE) system.

Both versions of the CTM are mounted under the passenger side end of the instrument panel, outboard of the instrument panel glove box opening. Refer to Instrument Panel, Gauges and Warning Indicators/Audible Warning Device Module/Central Timer Module in the Replacement of Instrument Panel Systems for the service procedures.

Refer to Instrument Panel, Gauges and Warning Indicators/Audible Warning Device Control Module/Central Timer Module in the Diagnosis and Testing of Wiper and Washer Systems. For diagnosis of the high-line version of the CTM or the CCD data bus, a DRB scan tool and the proper Diagnostic Procedures are recommended. The CTM cannot be repaired and, if faulty or damaged, it must be replaced.

Both the base and the high-line versions of the CTM support the intermittent wipe and wipe-after-wash features, but only the high-line CTM supports the speed sensitive intermittent wipe. The intermittent wipe relay is one of the outputs that both the base and the high-line versions of the CTM can control. Each CTM is programmed to energize or de-energize the intermittent wipe relay in response to certain inputs from the windshield wiper and washer switches and from the windshield wiper motor park switch.

For the speed sensitive intermittent wipe feature, the high-line CTM also uses vehicle speed messages, which are received on the CCD data bus from the Powertrain Control Module (PCM).

See Central Timer Module in the Diagnosis of the base version of the CTM. For diagnosis of the high-line version of the CTM or the CCD data bus, a DRB scan tool and the proper Diagnostic Procedures are recommended. The CTM cannot be repaired and, if faulty or damaged, it must be replaced.

The power lock and Remote Keyless Entry (RKE) systems are two of the systems that the high-line CTM controls. The high-line CTM receives hard-wired inputs from the power lock switches, CCD message inputs from the Powertrain Control Module (PCM) and Airbag Control Module (ACM), and coded radio signal inputs from the RKE transmitters. In response to those and many other inputs, the internal programming of the CTM sends the proper outputs to control the power lock motors, the horn relay, and the courtesy lamps.

Some of the features and functions of the power lock and Remote Keyless Entry (RKE) systems made possible because of the communication of the CTM on the CCD data bus network include:
- A door-lock inhibit feature which prevents the power lock system from being energized with a power door lock switch if the key is in the ignition and/or the headlamps are on. However, the locks can still be operated manually, with a key, or energized with the RKE transmitter.
- A Panic Mode feature which can provide additional personal security and protection. When the Panic button on the RKE transmitter is depressed the vehicle horn will pulse, the headlights will flash, and the interior lights will illuminate on the vehicle for about three minutes, or until the Panic button is depressed a second time. A vehicle speed of about 24 kilometers-per-hour (15 miles-per-hour) will also cancel the panic mode.
- An enhanced accident response feature will unlock both doors, then prevent the power door locks from locking the doors for a predetermined time interval, after receiving a CCD message from the ACM indicating a frontal impact of the vehicle requiring airbag deployment.This feature will also turn on the courtesy lamps ten seconds after receiving the ACM deployment message, if the CCD vehicle speed message from the PCM indicates that the vehicle is not moving. Of course, these responses are dependent upon functional battery power and wiring circuitry following the impact.
- Rolling door locks is a programmable feature of the power lock system. This feature will automatically lock all of the doors after the vehicle reaches a speed of about 24 kilometers-per-hour (15 miles-per-hour) or greater. This feature will also lock the doors if a door is opened, then closed again, at any speed above 24 kilometers-per-hour (15 miles-per-hour).
- A programmable feature of the RKE system is the enabling or disabling of the horn chirp following the RKE Lock function. This feature can be enabled or disabled and, if enabled, the horn chirp duration (twenty or forty milliseconds) can be selected.

The programmable features of the CTM can be enabled or disabled using the DRB scan tool and the proper Diagnostic Procedures. For diagnosis of the high4ine version of the CTM or of the CCD data bus, a DRB scan tool and the proper Diagnostic Procedures are recommended. The CTM cannot be repaired and, if faulty or damaged, it must be replaced.

One of the features that the high-line CTM supports and controls is the Vehicle Theft Security System (VTSS). In the VTSS, the CTM receives hard-wired inputs from the door jamb, door lock cylinder, and ignition switches. The programming in the CTM allows it to process the information from these inputs and send control outputs to energize or de-energize the headlamp relay, horn relay, and the security lamp. The CTM also sends CCD data bus messages to the Powertrain Control Module (PCM) to control the engine no-run feature of the VTSS.

The CTM also contains the receiver and control logic for the power lock and Remote Keyless Entry (RKE) systems, which are integrated into the arming, disarming, and triggering functions of the VTSS.

For diagnosis of the high-line version of the CTM or of the CCD data bus, a DRB scan tool and the proper Diagnostic Procedures are recommended. The CTM cannot be repaired and, if faulty or damaged, it must be replaced.

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