Power Lock Systems: Notes
DESCRIPTION
The power lock system has two subsystems. They are:
- Remote Keyless Entry (RKE) - Standard Equipped
- Passive Entry (PE) - Available Option
These systems can contain the following components:
| 1. | Refer to LOW FREQUENCY (LF) ANTENNA . |
| 2. | Refer to DISPLAY SCREEN MODULE (DSM) AND RADIO . |
| 3. | Refer to DOOR CONTROL MODULES (DCM) - DRIVER DOOR MODULE (DDM) AND PASSENGER DOOR MODULE (PDM) - Driver Door Module (DDM) and Passenger Door Module (PDM). |
| 4. | Refer to SMART HANDLE . |
| 5. | Refer to OVERHEAD CONSOLE TAILGATE RELEASE SWITCH . |
| 6. | Refer to POWER LOCK AJAR SWITCH - Integral to the latch and motor unit. Refer to POWER LOCK MOTOR - Integral to the latch and motor unit. |
| 7. | Refer to POWER LOCK SWITCH . |
| 8. | Refer to INSTRUMENT PANEL CLUSTER (IPC) . |
| 9. | Refer to BODY CONTROL MODULE (BCM) . |
| 10. | Refer to POWERTRAIN CONTROL MODULE (PCM) . |
| 11. | Refer to VEHICLE SPEED SIGNAL (VSS) . |
| - | Refer to DOOR LOCK CYLINDER . |
| - | Refer to RADIO FREQUENCY HUB (RFH) MODULE . |
| - | Refer to KEY FOB (FOBIK) . |
OPERATION
Power Locks
The power lock system uses non-switched battery current received through a fused B(+) fuse in the BCM so that the system remains operational regardless of the ignition switch position. The BCM is the primary power lock system controller. The power lock switches are hardwired to their respective DDM or PDM. The BCM, the DDM and the PDM all communicate with each other and with other electronic modules in the vehicle over the Controller Area Network (CAN) data bus.
When a DDM/PDM receives an input from a power lock switch, it sends the appropriate electronic Lock Request or Unlock Request message to the BCM over the CAN - Interior High Speed (CAN-IHS) data bus. The BCM responds to these request messages by providing the appropriate outputs to each of the power lock motors that lock or unlock the doors and Liftgate. The BCM requests that the RFH to search for a keyfob to identify the location of the keyfob passively. The BCM also stores the power lock system Customer Programmable feature settings received over the CAN data bus from the radio. The BCM uses these settings and internal programming along with hardwired and electronic message inputs to determine the proper outputs needed to produce each of the appropriate power lock system features.
The power lock system circuits are continually monitored and controlled by the microprocessor and software contained within the BCM. When the BCM monitors a problem in any of the power lock system circuits or components, it stores a fault code or Diagnostic Trouble Code (DTC) in its memory circuit.
Remote Keyless Entry
The RKE system uses non-switched battery current received through a fused B(+) fuse in the BCM so that the system remains operational regardless of the ignition switch position. The RFH is the primary RKE system controller. The RFH validates the vehicle access code of each key fob from which it receives RF signal inputs. It ignores requests from any key fob for which it has no stored vehicle access code.
If the vehicle is equipped with remote start, the RFH uses a remote start antenna located in the "D" pillar for all key fob signal communications. If the vehicle is not equipped with remote start, the RFH uses its own LF internal antenna for signal communications.
The RFH communicates and shares resources with the BCM and many other electronic modules in the vehicle over the CAN data bus. The RFH also stores the RKE system Customer Programmable feature settings received over the CAN data bus from the radio. When the RFH receives an input from a valid key fob, it uses these settings and internal programming to send the appropriate electronic request messages to the BCM and other electronic modules over the CAN data bus to invoke the proper RKE system features and responses.
The RKE system circuits and key fob inputs are continually monitored by the RFH. When the RFH monitors a problem in any of the RKE system circuits or key fobs, it stores a DTC in its memory circuit.
Passive Entry
In the Passive Entry Keyless Go (PEKG) system the doors are unlocked passively; however, they must still be locked actively after exiting the vehicle using the capacitive Lock button on either front door smart handle. When the system senses a hand approaching the capacitive switch in the handle or detects a button press of the liftgate switch, it sends out challenge messages through the LF antennas to authenticate the presence and location of a valid key fob.
The key fob responds by sending an Ultra High Frequency (UHF) message back to the receiver within the RFH module. If the RFH module determines the key fob is valid and that it is located outside the vehicle in the same zone or vicinity as the door handle or liftgate handle switch being activated, an electronic Unlock Request message over the CAN data bus to the BCM to automatically unlock the vehicle and allow entry.
The PEKG system circuits and key fob inputs are continually monitored by the software contained within the RFH module. When the RFH module monitors a problem in any of the PEKG system circuits or key fob inputs, it stores a DTC in its memory circuit.
Some features of the Power Lock system:
Automatic Door Locking:
Automatic door locking automatically locks any unlocked door when the vehicle speed exceeds a calibrated speed. Note that only the doors are considered and not the liftgate or hood.
Automatic Door Unlocking:
Automatic door unlocking automatically unlocks the doors after they were automatically locked when the vehicle speed has returned to zero, the transmission shift lever is in the Neutral or Park positions and the driver side front door is opened. Note that only the doors are considered and not the liftgate or hood.
Enhanced Accident Response System:
In the event of a vehicle impact that causes airbag deployment but leaves vehicle electrical power intact, the Enhanced Accident Response System (EARS) automatically turns off the supply of fuel to the engine, turns on the interior courtesy lamps, turns on the hazard warning flashers and unlocks the doors after the vehicle speed has returned to zero. This helps emergency responders in their efforts to render the appropriate assistance. The courtesy lamps and hazard flashers remain on as long as the battery has power or until the key is removed from the ignition.
Illuminated Entry:
Automatic illumination of the interior and exterior courtesy lamps when the vehicle is unlocked using the power lock system.