Power Door Child Lock Malfunction
Power Door Child Lock Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The child door lockout switch is on the driver door lock/window switch and controls the child locks on the rear doors as well as the rear window switches. When the body control module (BCM) receives a command from the window lockout switch, it will apply voltage to the door lock security relay coil, this will energize the relay and the contact within the relay will then direct the voltage to lock the left rear and right rear child locks and then isolate them from the normal door lock system to prevent the rear doors from being opened by using the interior rear door handles.
The BCM monitors the voltage level of the rear lock status signal circuits to determine if the rear door latches have been locked out. A switch within the rear door latch will be open or closed depending upon the lockout status of the rear latch. If the rear latches are not locked out, the switch will be open and the BCM will allow normal functions of the rear window switches. If the latches have been lockout, the switch will be closed, pulling the voltage within the signal circuit to 0 volts and the BCM will send a serial data message to the rear window switches which will disable the functions of the rear windows from the local rear window switches
Reference Information
Schematic Reference
Door Lock/Indicator Schematics Door Lock/Indicator Schematics
Connector End View Reference
Component Connector End Views Outside Rearview Mirror - Driver
Description and Operation
Power Door Locks Description and Operation Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the operation of both interior rear door handles do not open the rear doors when commanding the Child Security Lock Motors ON with a scan tool.
• If both interior rear door handles open the rear doors
Refer to Circuit/System Testing - Security Lockout Inoperative.
• If a single interior rear door handle opens the rear door
Refer to Circuit/System Testing - Single Door Security Lockout Malfunction.
• If both interior door handles do not open the rear doors
3. Verify the operation of both interior rear door handles will open the rear doors when commanding the Child Security Lock Motors OFF with a scan tool.
• If both interior rear door handles do not open the rear doors
Refer to Circuit/System Testing - Security Lockout Inoperative.
• If a single interior rear door handle does not open the rear door
Refer to Circuit/System Testing - Single Door Security Lockout Malfunction.
• If both interior door handles open the rear doors
4. Verify the operation of both rear window switches do not open the rear windows when commanding the Child Security Lock Motors ON with a scan tool.
• If a rear window switch continues to function
Refer to Circuit/System Testing - Rear Window Lockout Inoperative.
• If the rear window switch is inoperative
5. Verify the scan tool Window Lockout Switch parameter changes between On and Off when pressing the lockout switch on the driver window switch.
• If the parameter does not change
Replace the S79D window switch - driver.
• If the parameter changes
6. All OK.
Circuit/System Testing
Security Lockout Inoperative
1. Ignition OFF and all vehicle systems OFF, disconnect the X2 harness connector at the X51A fuse block-instrument panel. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 6 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Connect a test lamp between the control circuit terminal 8 and ground, ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the Child Security Lock Motors ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the K9 body control module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 body control module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K9 body control module.
• If the test lamp turns ON and OFF
5. Replace the X51A fuse block-instrument panel.
Single Door Security Lockout Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate rear A23 door latch assembly. Ignition ON.
2. Connect a test lamp between control circuit terminals listed below:
* A23LR door latch assembly-left rear - control circuit terminal 4 and control circuit terminal 7
* A23RR door latch assembly-right rear - control circuit terminal 2 and control circuit terminal 9
3. Verify the test lamp turns ON and OFF when commanding the Child Security Lock Motors ON and OFF with a scan tool.
• If the test lamp remains OFF during either of the commands
1. Ignition OFF, disconnect the harness connector at the K9 body control module.
2. Test for infinite resistance between each control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K9 body control module.
• If the test lamp turns ON during each of the commands
4. Test or replace the rear A23 door latch assembly.
Rear Window Lockout Inoperative
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate rear A23 door latch assembly. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal listed below and ground:
* A23LR door latch assembly - left rear - ground circuit terminal 8
* A23RR door latch assembly - right rear - ground circuit terminal 3
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify the scan tool Rear Child Security Lock Switch parameter is Inactive.
• If not Inactive
1. Ignition OFF, disconnect the harness connector at the K9 body control module.
2. Test for infinite resistance between the signal circuit terminal listed below and ground.
* A23LR door latch assembly-left rear - signal circuit terminal 9
* A23RR door latch assembly-right rear - signal circuit terminal 4
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K9 body control module.
• If Inactive
5. Install a 3 A fused jumper wire between the signal and the ground circuit terminals listed below:
* A23LR door latch assembly-left rear - signal circuit terminal 9 and ground circuit terminal 8
* A23RR door latch assembly-right rear - signal circuit terminal 4 and ground circuit terminal 3
6. Verify the scan tool Rear Child Security Lock Switch parameter is Active.
• If not Active
1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 body control module.
• If Active
7. Test or replace the rear A23 door latch assembly.
Component Testing
Door Latch Test
1. Ignition OFF, disconnect the harness connector at the appropriate rear A23 door latch assembly.
2. Install a 30 A fused jumper wire between one of the control terminals and 12 V. Momentarily install a jumper wire between the other control terminal and ground. Reverse the jumper wires at least two times, the rear A23 door latch assembly should perform the LOCK and UNLOCK functions.
• If the function does not perform the LOCK and UNLOCK function
Replace the rear A23 door latch assembly.
• If the function performs the LOCK and UNLOCK function
3. All OK
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Rear Side Door Lock Replacement Rear Side Door Lock Replacement
* Fuse Block Replacement Fuse Block Replacement
* Control Module References Control Module References for BCM replacement, programming and setup