Power Lock Systems — 1998 Jeep Grand Cherokee ZJ Export Service Manual
Pages 481–488 · 8 pages · 3 words repaired
REMOTE KEYLESS ENTRY SYSTEM
The Remote Keyless Entry (RKE) system is a radio frequency system that allows the use of a remote radio transmitter to control the power lock and illuminated entry systems. If the vehicle is so equipped, the RKE transmitter can also control the memory seat, memory mirror, memory radio, and the vehicle theft alarm systems.
The RKE system consists of the remote key fob transmitter and a radio receiver with program logic, which is integral to the Passenger Door Module (PDM). The RKE system can retain the vehicle access codes of two transmitters. The transmitter codes are retained in memory, even if the battery is disconnected.
If a transmitter is faulty or lost, new transmitter vehicle access codes can be programmed into the system using a DRB scan tool and the proper Diagnostic Procedures manual. The RKE system for this vehicle also features a programmable horn chirp feature. This feature allows the customer the option of having the horn chirp request, which the RKE receiver issues as an audible indication that a valid Lock signal has been received from the RKE transmitter, enabled or disabled by the dealer.
On models so equipped, a function of the RKE system made possible by the connection of the PDM to the Chrysler Collision Detection (CCD) data bus network is a panic mode. If the Panic button on the RKE transmitter is depressed, the horn will sound and the exterior lights will flash 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.
MEMORY SYSTEM
An electronic memory system is an available option on this model. The memory system is able to store and recall the driver side power seat positions (including power lumbar and recliner positions), and both outside power mirror positions for two drivers. For vehicles with a radio connected to the Chrysler Collision Detection (CCD) data bus network, the memory system is also able to store and recall ten radio station presets (including last station tuned) for two drivers. The memory system will automatically return to all of these settings when the corresponding button (Driver 1 or 2) of the memory switch on the driver side front door trim panel is depressed, or when the doors are unlocked using the corresponding (Driver 1 or 2) Remote Keyless Entry (RKE) transmitter.
The Driver Door Module (DDM) receives hardwired input from the memory set/select switch on the driver side front door trim panel. The DDM also receives messages on the CCD data bus from the RKE receiver in the Passenger Door Module (PDM) for the memory select function. The DDM processes these inputs and sends messages to the radio (if CCD data bus capable), the PDM, and the Memory Seat Module (MSM) on the CCD data bus for memory recall.
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.
This group covers only the conventional diagnostic procedures for the power lock and RKE system components. For diagnosis of the memory system, the use of a DRB scan tool and the proper Diagnostic Procedures manual are recommended. For additional information on the features and functions of the memory system, refer to the owner's manual in the vehicle glove box.
DESCRIPTION AND OPERATION
POWER LOCK SWITCH
The power locks are controlled by a two-way switch that is integral to the Driver Door Module (DDM) and the Passenger Door Module (PDM) mounted in the trim panel of its respective front door. Each switch is illuminated by a light-emitting diode when the ignition switch is turned to the On position. The power lock switch provides a lock or unlock signal to the door module circuitry.
The power lock switches and their lamps cannot be repaired. If the switches are damaged or faulty, the entire PDM or DDM unit must be replaced.
DOOR MODULE
A Driver Door Module (DDM) and a Passenger Door Module (PDM) are used on this model to control and integrate many of the electronic features and functions on the vehicle. Each door module houses both the front power lock and power window switches. The DDM also houses individual switches for each passenger door power window, a power window lockout switch and the power mirror switch.
The DDM and PDM communicate with each other, and with other vehicle modules 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, internal controller hardware, and 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 DDM circuitry controls the output to the driver front door power lock motor. The PDM circuitry controls the output to the power lock motors for the remaining doors and the liftgate. When a door lock switch is actuated, the door module circuitry for that switch sends a message to the other door module on the CCD data bus to activate the output to the remaining power lock motor(s).
Some of the features and functions of the power lock and Remote Keyless Entry (RKE) systems made possible because of the communication of the door modules on the CCD data bus network include:
• A door-lock inhibit feature which prevents the power lock system from being energized with a door switch if the key is in the ignition and/or the headlamps are on with the driver door open. However, the locks can still be operated manually with a key or energized with the RKE transmitter.
• A rolling door locks feature will automatically lock all of the doors and the liftgate, 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 milesper-hour). Rolling door locks is a programmable feature of the power lock system. This feature can be enabled or disabled using the DRB scan tool and the proper Diagnostic Procedures manual.
• An RKE system panic mode, on models so equipped. If the Panic button on the RKE transmitter is depressed, the horn will sound and the exterior lights will flash 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.
• 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 using the DRB scan tool and the proper Diagnostic Procedures manual.
• Another programmable feature is the enabling or disabling of the RKE system unlocking the driver door only, or all doors upon one depression of the transmitter Unlock button. If the driver door only mode is enabled, a second depression of the Unlock button within five seconds will unlock all of the doors and the liftgate. This feature can be enabled or disabled using the DRB scan tool and the proper Diagnostic Procedures manual.
For diagnosis of the DDM, PDM, or the CCD data bus network, a DRB scan tool and the proper Diagnostic Procedures manual are recommended. The DDM and the PDM cannot be repaired and, if damaged or faulty, they must be replaced.
BODY CONTROL MODULE
A Body Control Module (BCM) is used on this model to control and integrate many of the electronic functions and features included on the vehicle. The BCM 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.
One of the functions and features that the BCM supports and controls on models so equipped, is the Remote Keyless Entry (RKE) Panic Mode. The BCM receives input from the RKE receiver in the Passenger Door Module (PDM) on the CCD data bus. The programming in the BCM allows it to process the information from this input and send control outputs to the headlamp relay, horn relay, and park lamp relay to accomplish the panic mode functions.
The BCM is mounted under the driver side outboard end of the instrument panel, behind the instrument panel support armature and below the outboard switch pod. Refer to Group 8E - Instrument Panel Systems for the removal and installation procedures. For diagnosis of the BCM or the CCD data bus, the use of a DRB scan tool and the proper Diagnostic Procedures manual are recommended. The BCM can only be serviced by an authorized electronic repair station. Refer to the latest Warranty Policies and Procedures manual for a current listing of authorized electronic repair stations.
POWER LOCK MOTOR
In the power lock and Remote Keyless Entry (RKE) systems, the locks are actuated by a reversible electric motor mounted within each door and the liftgate. The driver front door lock motor direction is controlled by the battery and ground feeds from the Driver Door Module (DDM). The remaining door lock motors and the liftgate lock motor are controlled by the battery and ground feeds from the Passenger Door Module (PDM).
The power lock motors cannot be repaired and, if faulty or damaged, the entire motor must be replaced.
CIRCUIT BREAKER
An automatic resetting circuit breaker in the junction block is used to protect the power lock system circuit. The circuit breaker can protect the system from a short circuit, or from an overload condition caused by an obstructed or stuck lock motor, latch, or lock linkage.
The circuit breaker cannot be repaired and, if faulty, it must be replaced.
REMOTE KEYLESS ENTRY TRANSMITTER
The Remote Keyless Entry (RKE) system transmitter is equipped with three buttons, labeled Lock, Unlock, and Panic. It is also equipped with a key ring and is designed to serve as a key fob. The operating range of the transmitter radio signal is up to 7 meters (23 feet) from the RKE receiver.
Each transmitter has a different vehicle access code, which must be programmed into the memory of the RKE receiver in the vehicle in order to operate the RKE system. In addition, vehicles with the memory seat/mirror/radio system must have their access codes programmed into the receiver so that the molded-in numbers “1” or “2” on the back of the transmitter case coincide with the memory “1” and “2” buttons of the memory set switch in the vehicle.
The transmitter operates on two Duracell DL2016 (or equivalent) batteries. Typical battery life is from one to two years. The transmitter cannot be repaired and, if faulty or damaged, it must be replaced.
REMOTE KEYLESS ENTRY RECEIVER
The Remote Keyless Entry (RKE) receiver is a radio frequency unit contained in the Passenger Door Module (PDM). The PDM also contains the program circuitry for the RKE system. The PDM is located inside the passenger side front door, and is secured to the door trim panel.
The RKE receiver has a memory function to retain the vehicle access codes of two RKE transmitters. The receiver is designed to retain the transmitter codes in memory, even if the battery is disconnected.
The RKE receiver is energized by one of three messages from the RKE transmitter; Unlock, Lock, or Panic. The PDM circuitry responds to these messages to lock or unlock the power lock motors that it controls. The PDM circuitry also puts Lock, Unlock, and Panic messages on the Chrysler Collision Detection (CCD) data bus.
These messages will result in the Driver Door Module (DDM) locking or unlocking the driver side front door, and/or the Body Control Module (BCM) initiating the proper Panic, Horn Chirp, Illuminated Entry, and Vehicle Theft Alarm functions. If the vehicle is equipped with the optional memory system, the proper CCD Unlock message will also result in the DDM initiating its memory recall functions.
For diagnosis of the RKE receiver, the PDM, the DDM, or the CCD data bus, refer to the proper Diagnostic Procedures manual. The RKE receiver is only serviced as a unit with the PDM and, if faulty or damaged, the PDM unit must be replaced.
DIAGNOSIS AND TESTING
POWER LOCK AND REMOTE KEYLESS ENTRY SYSTEM
As a preliminary diagnosis for the power lock and Remote Keyless Entry (RKE) systems, note the system operation while you actuate both the Lock and Unlock functions with the power lock switches and the RKE transmitter. Then, proceed as follows:
• If the power lock system fails to function with either the power lock switches or the RKE transmitter, see the Circuit Breaker diagnosis in this group.
• If the power lock system functions with both power lock switches, but not with the RKE transmitter, see the Remote Keyless Entry Transmitter diagnosis in this group.
• If the power lock system functions with the RKE transmitter, but not with one or both power lock switches, see the Door Module diagnosis in this group.
• If one power lock motor fails to operate with the power lock switches or the RKE transmitter, see the Power Lock Motor diagnosis in this group.
CIRCUIT BREAKER
For circuit descriptions and diagrams, refer to 8W-61 - Power Door Locks in Group 8W - Wiring Diagrams.
(1) Locate the circuit breaker in the junction block. Pull out the circuit breaker slightly, but be sure that the terminals still contact the terminals in the junction block cavities.
(2) Connect the negative lead of a 12-volt DC voltmeter to a good ground.
(3) With the voltmeter positive lead, check both terminals of the circuit breaker for battery voltage.
If only one terminal has battery voltage, the circuit breaker is faulty and must be replaced. If neither terminal has battery voltage, repair the open circuit from the Power Distribution Center (PDC) as required. If the circuit breaker checks OK, but no power locks operate, see the diagnosis for the Door Module in this group.
DOOR MODULE
NOTE: The following tests may not prove conclusive in the diagnosis of this component. The most reliable, efficient, and accurate means to diagnose this system involves the use of a DRB scan tool and the proper Diagnostic Procedures manual.
Remember, the DDM circuitry controls the output to the driver side front door power lock motor. The PDM circuitry controls the output to the power lock motors for the remaining doors and the liftgate. For circuit descriptions and diagrams, refer to 8W-61 - Power Door Locks in Group 8W - Wiring Diagrams.
(1) Disconnect and isolate the battery negative cable. Remove the front door trim panel. Go to Step 2.
(2) Check the 12-way door module wire harness connector to see that it is fully seated in the door module receptacle. If OK, go to Step 3. If not OK, install the wire harness connector properly. (3) Unplug the 12-way door module wire harness connector from the door module. Check for continuity between the ground circuit cavity of the door module wire harness connector and a good ground. There should be continuity. If OK, go to Step 4. If not OK, repair the open circuit as required.
(4) Connect the battery negative cable. Check for battery voltage at the fused B(+) circuit cavity of the 12-way door module wire harness connector. If OK, go to Step 5. If not OK, repair the open circuit as required.
(5) Disconnect and isolate the battery negative cable. Check for continuity between the door lock driver circuit cavity of the 12-way door module wire harness connector and a good ground. Repeat the check for the door unlock driver circuit cavity of the door module wire harness connector. In each case there should be no continuity. If OK, go to Step 6. If not OK, repair the short circuit as required.
(6) Plug the 12-way door module wire harness connector back into the door module. Unplug the inoperative power lock motor wire harness connector. Connect the battery negative cable. Go to Step 7.
(7) Connect the probes of a reversible DC digital voltmeter to the body wire harness half of the power lock motor wire harness connector. Observe the voltmeter while actuating the power lock switch in the lock and unlock directions. There should be a short 12-volt voltage spike as the switch is moved to both the lock and unlock positions, and no voltage in the neutral position. If OK, see the diagnosis for the Power Lock Motor in this group. If not OK, replace the faulty door module.
POWER LOCK MOTOR
Remember, the Driver Door Module (DDM) circuitry controls the output to the driver side front door power lock motor. The Passenger Door Module (PDM) circuitry controls the output to the power lock motors for the remaining doors and the liftgate. For circuit descriptions and diagrams, refer to 8W-61 - Power Door Locks in Group 8W - Wiring Diagrams.
(1) Check each power lock motor for correct operation while moving the power lock switch to both the Lock and Unlock positions. If all of the power lock motors are inoperative, go to Step 2. If one power lock motor is inoperative, go to Step 3.
(2) If all of the power lock motors except the driver side front door are inoperative, the problem may be caused by one shorted motor. Unplugging a shorted power lock motor from the power lock circuit will allow the good power lock motors to operate. Unplug each PDM-controlled power lock motor wire harness connector, one at a time, and recheck both the lock and unlock functions by operating the power lock switch. If all of the PDM-controlled power lock motors are still inoperative after the above test, check for a short or open circuit between the power lock motors and the PDM. If unplugging one power lock motor causes the other motors to become functional, go to Step 3 to test the unplugged motor.
(3) Once it is determined which lock motor is inoperative, that motor can be tested as follows. Unplug the wire harness connector at the inoperative motor. Apply 12 volts to the motor terminals to check its operation in one direction. Reverse the polarity to check the operation in the other direction. If OK, repair the short or open circuits to the DDM or PDM as required. If not OK, replace the faulty power lock motor.
REMOTE KEYLESS ENTRY TRANSMITTER
(1) Replace the Remote Keyless Entry (RKE) transmitter batteries. See Remote Keyless Entry Transmitter Battery Replacement in this group for the procedures. Test each of the transmitter functions. If OK, discard the faulty batteries. If not OK, go to Step 2.
(2) Perform the Remote Keyless Entry Transmitter Programming procedure with the suspect transmitter and another known good transmitter. Use a DRB scan tool, as described in the proper Diagnostic Procedures manual.
(3) Test the RKE system operation with both transmitters. If both transmitters fail to operate the power lock system, use a DRB scan tool and the proper Diagnostic Procedures manual for further diagnosis of the RKE system. If the known good transmitter operates the power locks and the suspect transmitter does not, replace the faulty transmitter.
NOTE: Be certain to perform the Remote Keyless Entry Transmitter Programming procedure again following this test. This procedure will erase the access code of the test transmitter from the RKE receiver.
POWER LIFTGLASS RELEASE SYSTEM
For circuit descriptions and diagrams, refer to 8W-61 - Power Door Locks in Group 8W - Wiring Diagrams.
(1) Check the fuse in the junction block. If OK, go to Step 2. If not OK, repair the shorted circuit or component as required and replace the faulty fuse.
(2) Check for battery voltage at the fuse in the junction block. If OK, go to Step 3. If not OK, repair the open circuit as required.
(3) Unplug the liftglass limit switch wire harness connector. Check for battery voltage at the fused B(+) circuit cavity of the limit switch wire harness connector. If OK, go to Step 4. If not OK, repair the open circuit as required.
(4) Check for continuity between the two terminals of the liftglass limit switch. There should be continuity with the liftgate latch unlocked, and no continuity with the latch locked. If OK, go to Step 5. If not OK, replace the faulty limit switch.
(5) Unplug the liftglass push button switch wire harness connector. With the liftgate latch unlocked, check for battery voltage at the liftglass limit switch output circuit cavity of the push button switch wire harness connector. If OK, go to Step 6. If not OK, repair the open circuit as required.
(6) Check for continuity between the two terminals of the liftglass push button switch. There should be no continuity. Depress the switch, there should now be continuity. If OK, go to Step 7. If not OK, replace the faulty push button switch.
(7) Unplug the liftglass release solenoid wire harness connector. Check for continuity between the ground circuit cavity of the wire harness connector and a good ground. There should be continuity. If OK, go to Step 8. If not OK, repair the open circuit as required.
(8) With the liftgate latch unlocked and the liftglass push button switch depressed, check for battery voltage at the liftglass push button output circuit cavity of the liftglass release solenoid wire harness connector. If OK, replace the faulty solenoid. If not OK, repair the open circuit as required.
SERVICE PROCEDURES
REMOTE KEYLESS ENTRY TRANSMITTER BATTERY REPLACEMENT
The Remote Keyless Entry (RKE) transmitter case snaps open and shut for battery access. To replace the RKE transmitter batteries:
(1) Using a trim stick or another suitable wide flat-bladed tool, gently pry at the center seam of the transmitter case halves near the key ring until the two halves unsnap.
(2) Lift the back half of the transmitter case off of the transmitter.
(3) Remove the two batteries from the transmitter. (4) Replace the two batteries with new Duracell DL2016, or their equivalent. Be certain that the batteries are installed with their polarity correctly oriented.
(5) Align the two transmitter case halves with each other, and squeeze them firmly together until they snap back into place.
REMOTE KEYLESS ENTRY TRANSMITTER PROGRAMMING
To program the Remote Keyless Entry (RKE) transmitter access codes into the RKE receiver in the Passenger Door Module (PDM) requires the use of a DRB scan tool. Refer to the proper Diagnostic Procedures manual for more information.
REMOVAL AND INSTALLATION
DOOR MODULE
Before replacing the door module, use a DRB scan tool to determine the current settings for the door module programmable features. These settings should be duplicated in the replacement door module using the DRB scan tool, before returning the vehicle to service.
(1) Disconnect and isolate the battery negative cable.
(2) Remove the bezel near the inside door latch release handle by inserting a straight-bladed screwdriver in the notched end of the bezel and prying gently upwards.
(3) Remove the screw located beneath the bezel that secures the front door trim panel to the inner door panel (Fig. 1).
(4) Remove the trim cap and screw near the rear of the front door armrest.
(5) Remove the trim cap and screw at the upper front corner of the front door trim panel.
(6) Remove the screw located above the front door speaker grille on the front door trim panel.
(7) Using a trim stick or another suitable wide flat-bladed tool, gently pry the front door trim panel away from the door around the perimeter to release the trim panel retainers.
NOTE: To aid in the removal of the trim panel, start at the bottom of the panel.
(8) Pull the front door trim panel away from the inner door panel far enough to access and unplug the wire harness connectors from the door module and, if the vehicle is so equipped, from the front door courtesy lamp.
(9) Remove the five screws that secure the door module to the back of the front door trim panel (Fig. 2).
(10) Remove the door module from the trim panel. (11) Reverse the removal procedures to install. Tighten the mounting screws to 2.2 N·m (20 in. lbs.).
NOTE: If a new door module is installed, the programmable features must be enabled and/or disabled to the customer's preferred settings. Use a DRB scan tool and the proper Diagnostic Procedures manual to perform these operations.
POWER LOCK MOTOR
FRONT DOOR
The front door power lock motor is integral to the front door latch unit. If the front door power lock motor is faulty or damaged, the entire latch unit must be replaced. Refer to Group 23 - Body for the front door latch service procedures.
REAR DOOR
The rear door power lock motor is integral to the rear door latch unit. If the rear door power lock motor is faulty or damaged, the entire latch unit must be replaced. Refer to Group 23 - Body for the rear door latch service procedures.
LIFTGATE
(1) Disconnect and isolate the battery negative cable.
(2) Open the liftgate. (3) Remove the screws that secure the liftgate lower trim panel to the liftgate inner panel (Fig. 3).
(4) Using a trim stick or another suitable wide flat-bladed tool, gently pry the perimeter edges of the trim panel away from the liftgate inner panel to release the retainers.
NOTE: To aid in the removal of the trim panel, start at the bottom of the panel.
(5) Remove the liftgate trim panel from the vehicle.
(6) Reach through the liftgate inner panel access hole and disconnect the lock actuator motor linkage clip at the liftgate latch handle (Fig. 4).
(7) Remove the two screws that secure the power lock actuator motor to the liftgate inner panel (Fig. 5).
(8) Pull the power lock motor out through the liftgate inner panel access hole far enough to access the wire harness connector.
(9) Unplug the wire harness connector from the power lock motor.
(10) Remove the power lock motor from the liftgate.
(11) Reverse the removal procedures to install. Tighten the power lock actuator motor mounting screws to 3 N·m (28 in. lbs.).