Power Locks: Description and Operation
POWER DOOR LOCKSThe CTM controls the door lock actuation assemblies to handle locking and unlocking with the interior door lock switches or the RKE transmitter (key fob). There is also a door lock inhibit feature that prevents the power locking of the doors if the key is in the ignition or the headlamps are on and the left front door is open. However, the doors can still be locked using the RKE transmitter which allows the engine to run for warm up purposes.
Automatic (Rolling) Door Locks
When the doors are closed and the vehicle speed exceeds 15 MPH due to engine power (not just rolling) and all doors are closed, the CTM will lock the doors. The vehicle is shipped with the automatic door lock feature enabled, but may be disabled using the DRBIII or by the customer.
Door Lock Delay
If the CTM receives a signal to lock the doors and one or both of the auxiliary doors (side or rear) are open, the front doors will still lock. Five seconds after both of the auxiliary door are closed, the CTM will recycle the lock function.
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 vehicles that are not equipped with the optional Vehicle Theft Security System (VTSS), the power lock system control components are integral to a power lock and Remote Keyless Entry (RKE) module. Vehicles that are equipped with the VTSS option have their power lock system control components integral to a microprocessor-based Central Timer Module (CTM). Both power lock Systems allow all of the doors to be locked or unlocked electrically by operating the switch on either front door; however, the CTM-based power lock system offers several additional features that are not available with the power lock and RKE module-based system.
Both versions of the power lock system include the following major components, which are described in further detail elsewhere in this service information:
Power Lock Motors - A reversible electric motor integral to the door latch of each front door, or remotely mounted and operating the latch through a linkage rod within each side and rear door, locks or unlocks the door latch when provided with the appropriate electrical inputs.
Power Lock Switches - A power lock switch is secured in the mirror flag trim bezel near the front of each front door and allows the power lock system to be operated by either the driver or the front seat passenger.
The power lock system may also include some, but not all, of the following components, depending upon whether the vehicle is equipped with the optional VTSS:
Central Timer Module - A Central Timer Module (CTM) is used on this vehicle when it is equipped with the optional Vehicle Theft Security System (VTSS). The CTM is concealed under the instrument panel, where it is secured with three screws to the inboard side of the left center instrument panel support above the engine housing. The CTM provides the proper power lock system features based upon the monitored inputs. The CTM circuitry monitors hard wired switch inputs, as well as message inputs received from other vehicle electronic modules on the Chrysler Collision Detection (CCD) data bus network.
Door Cylinder Lock Switches - A resistor- multiplexed switch located on the back of each front door lock cylinder of models equipped with the optional VTSS, allows the power lock system to be operated using a key inserted in either the driver or passenger front door lock cylinder.
Power Lock and Remote Keyless Entry Module - A power lock and Remote Keyless Entry (RKE) module is used on vehicles that are not equipped with the optional Vehicle Theft Security System (VTSS). The power lock and RKE module is concealed under the instrument panel, where it is secured with two screws to the inboard side of the left center instrument panel support above the engine housing. The power lock and RKE module contains integrated circuitry and programming that allow it to provide the proper power lock system features based upon numerous hard wired inputs.
Some of the additional features of the power lock system found in vehicles with the VTSS option include:
Automatic Door Lock - The CTM provides an optional automatic door lock feature (also known as rolling door locks). This is a programmable feature.
Central Locking - The CTM provides a central locking/unlocking feature.
Door Lock Inhibit - The CTM provides a door lock inhibit feature.
Enhanced Accident Response - The 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 CTM are programmable using the DRB III scan tool. In addition, the 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.
Both versions of the power lock system allow all doors to be locked or unlocked electrically by operating the power lock switch on either front door mirror flag trim bezel. Both versions also include a delay door lock feature which, if a side or rear auxiliary door is open when a power lock system Lock input is received, will automatically lock all of the doors again about five seconds after all of the doors are closed. On vehicles that are also equipped with the optional Vehicle Theft Security System (VTSS), all doors may also be locked or unlocked using a key in either front door lock cylinder.
On vehicles with VTSS, if certain features have been electronically enabled, the locks may also be operated automatically by the Central Timer Module (CTM) based upon various other inputs. Those features and their inputs are:
Automatic Door Lock - If enabled, the 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 all 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 all doors are closed.
Central Locking - Vehicles equipped with a 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 all doors when either front door is locked or unlocked using a key.
Door Lock Inhibit - The 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 with 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 with a key in the ignition.
Enhanced Accident Response - If enabled, the 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 fuse block 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 both versions of the power lock system, the power lock switches direct a battery current Lock or Unlock request signal to the power lock and Remote Keyless Entry (RKE) module or the CTM, and the module energizes internal relays to direct the appropriate battery current and ground feeds to the power lock motors. The hard wired inputs or outputs of the power lock system can be diagnosed using conventional diagnostic tools and methods; however, for diagnosis of the CTM or the CCD data bus, the use of a DRB III scan tool is required. Refer to the appropriate diagnostic information.