Power Locks: Description and Operation
POWER DOOR LOCKSThe CTM controls the door lock actuator assemblies to handle locking and unlocking with the key fob or interior switch. There is also a door lock inhibit feature that prevents power locking of the doors if the ignition is OFF and the key is in the ignition. Automatic or rolling locks are included as a DRB III (R) programmable feature. If the vehicle is moving approximately 15 mph and approximately 10 degrees of throttle opening is seen by the PCM, (the PCM will send this info to the CTM Body Control Modulevia the CCD bus Information Bus) indicating acceleration, the CTM will cycle the lock actuators.
POWER LOCK SYSTEM
Two different power lock Systems are offered as optional factory-installed equipment on this model. Both power lock systems are offered only on models that are also equipped with power windows. On models without the optional Remote Keyless Entry (RKE) system, a base version of the Central Timer Module (CTM) is used. In this version of the power lock system, the power lock switches provide the only control over the operation of the power lock motors. On models with the optional RKE system, a high-line or premium version of the CTM is used to provide many electronic features and conveniences that are not possible with the base version CTM. In this power lock system, the power lock motors are controlled by the microprocessor-based high-line or premium version of the CTM based upon the CTM programming and electronic message inputs received from other electronic modules in the vehicle over the Chrysler Collision Detection (CCD) data bus network, Radio Frequency (RF) inputs received from the RKE transmitters, as well as many hard wired inputs.
Both versions of the power lock system include the following major components, which are described in further detail elsewhere:
Power Lock Motors - A reversible electric motor integral to the door latch of each front door locks or unlocks the front door latch when provided with the appropriate electrical inputs.
Power Lock Switches - A power lock switch integral to the power window/lock switch unit located near the forward end of the arm rest on each front door trim panel allows the power door lock system to be operated by either the driver or the front seat passenger.
On those models equipped with the optional RKE system, the power lock system also includes the following components, which are described in further detail elsewhere:
Central Timer Module - The high-line or premium Central Timer Module (CTM) is located under the driver side end of the instrument panel, inboard of the instrument panel steering column opening. The high-line or premium CTM contains a microprocessor and software that allow it to provide the many electronic functions and features not available with base version of the power lock system.
Door Cylinder Lock Switches - A resistor-multiplexed switch located on the back of each front door lock cylinder allows the power door lock system to be operated using a key inserted in either the driver or passenger front door lock cylinder.
Some of the additional features of the power lock system found in vehicles with the RKE system option include:
Automatic Door Lock - The high-line/premium CTM provides an optional automatic door lock feature (also known as rolling door locks). This is a programmable feature.
Central Locking - The high-line/premium CTM provides an optional central locking/unlocking feature.
Door Lock Inhibit - The high-line/premium CTM provides a door lock inhibit feature.
Enhanced Accident Response - The high-line/premium CTM provides an optional enhanced accident response feature. This is a programmable feature.
Hard wired circuitry connects the power lock system components to the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the power lock system components through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.
Many of the electronic features in the vehicle controlled or supported by the high-line or premium versions of the CTM are programmable using the DRB III scan tool. In addition, the high-line/premium CTM software is Flash compatible, which means it can be reprogrammed using Flash reprogramming procedures. However, if any of the CTM hardware components are damaged or faulty, the entire CTM unit must be replaced. The power lock system components and the hard wired inputs or outputs of the CTM can be diagnosed using conventional diagnostic tools and methods; however, for diagnosis of the high-line or premium versions of the CTM or the CCD data bus, the use of a DRB III scan tool is required. Refer to the appropriate diagnostic information.
All versions of the power lock system allow both doors to be locked or unlocked electrically by operating the power lock switch on either front door trim panel. On vehicles that are also equipped with the optional Remote Keyless Entry (RKE) system, both doors may also be locked or unlocked using a key in either front door lock cylinder, or by using the RKE transmitter. On vehicles with the RKE system, if certain features have been electronically enabled, the locks may also be operated automatically by the high-line or premium Central Timer Module (CTM) based upon various other inputs. Those features and their inputs are:
Automatic Door Lock - If enabled, the high-line/premium CTM will automatically lock the doors when it receives a message from the Powertrain Control Module (PCM) indicating that the vehicle speed is about 24 kilometers-per-hour (15 miles-per-hour) or greater. The CTM also monitors the door ajar switches, and will not activate the automatic door lock feature until both doors have been closed for at least five seconds. If this feature is enabled and a door is opened after the vehicle is moving, the CTM will also lock the doors five seconds after both doors are closed.
Central Locking - Vehicles equipped with a high-line/premium CTM also have a resistor-multiplexed door cylinder lock switch mounted to the back of the door lock cylinder within each front door. The CTM continually monitors the input from these switches to provide the central locking/unlocking feature. The CTM will automatically lock or unlock both front doors when either front door is locked or unlocked using a key.
Door Lock Inhibit - The high-line/premium CTM receives inputs from the key-in ignition switch, the headlamp switch, and the door ajar switches. The logic within the CTM allows it to monitor these inputs to provide a door lock inhibit feature. The door lock inhibit feature prevents the power lock system from being energized with a power lock switch input if the driver door is open with the headlamps on or the key still in the ignition switch. However, the locks can still be operated with the manual door lock button or with a key in the door lock cylinder, and the power locks will still operate using the RKE transmitter while the driver door is open with the headlamps ON or a key in the ignition.
Enhanced Accident Response - If enabled, the high-line/premium CTM provides an enhanced accident response feature. This feature uses electronic message inputs received by the CTM from the Airbag Control Module (ACM) to determine when an airbag has been deployed. The CTM also monitors the state of the power lock system and the vehicle speed messages from the PCM in order to provide this feature. If the airbag has been deployed and the vehicle has stopped moving, the CTM will automatically unlock the doors, prevent the doors from being locked, and turn on the courtesy lamps inside the vehicle. Of course, these responses are dependent upon a functional battery and electrical circuitry following the impact.
All versions of the power lock system operate on battery current received through a fused B(+) circuit from a fuse in the Junction Block (JB) so that the system remains functional, regardless of the ignition switch position. Also, in both versions of the power lock system, each power lock switch receives battery current independent of the other. In vehicles with the base version of the power lock system, the driver side power lock switch receives ground through the body wire harness. A single wire take out of the body wire harness with an eyelet terminal connector is secured by a ground screw to the lower left B-pillar (regular cab, extended cab) or lower left quarter inner panel (quad cab). The passenger side power lock switch receives ground through the driver side power lock switch in the base version of the power lock system. The base version power lock switches direct the appropriate battery current and ground feeds to the power lock motors. In the power lock system for vehicles with the RKE system, the power lock switches direct a battery current Lock or Unlock request signal to the high-line or premium CTM, and the CTM energizes internal relays to direct the appropriate battery current and ground feeds to the power lock motors.