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 Instructionsprovides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit/System Description

The child door lockout switch on the radio/HVAC display controls the child locks on the rear doors. The lockout switch is an input to the body control module (BCM) and the BCM controls the CHILD SECURITY relay. When the BCM receives a command from the child door lockout switch, it will apply voltage to the CHILD 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.

Reference Information
Schematic Reference

* Door Lock/Indicator Schematics Door Lock/Indicator Schematics
* Body Control System Schematics [1][2]Body Control Systems

Connector End View Reference

Component Connector End Views Connector End Views By Name
Description and Operation

Power Door Locks Description and Operation Description and Operation
Electrical Information Reference

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Circuit Testing Circuit Testing
* Wiring Repairs Wiring Repairs
* Connector Repairs Connector Repairs

Scan Tool Reference

Control Module References Control Module Referencesfor scan tool information

Circuit/System Verification

1. Operate the door locks to LOCK and UNLOCK by pressing the appropriate switch on the central door lock switch. Each interior door lock knob should move between LOCK and UNLOCK.

• If one or more doors do not LOCK or UNLOCK, refer to Power Door Lock Malfunction - DTC B3125, B3130, or B3135 B3125.

2. Ignition ON observe the scan tool child security lock motors command while pressing the child lockout switch. The value should change from Inactive to Lock and from Inactive to Unlock each time the switch is pressed.

• If a value does not change, refer to Child Lockout Switch Malfunction.

3. With all the doors locked, command the child security lockout by pressing the security lockout switch, the interior rear door handles should not open the doors when used and the lockout indicator should illuminate.

• If both interior rear door handles continue to function, refer to Child Security Door Lockout Inoperative.
• If the left or right interior rear door handles continue to function, refer to Child Security Door Lockout Malfunction.
• If the lockout indicator flashes ON and OFF, refer to Child Security Door Lockout Inoperative or Child Security Door Lockout Malfunction.
• If the lockout indicator is always ON or always OFF, refer to Lockout Indicator Malfunction.

Circuit/System Testing

Child Lockout Switch Malfunction
1. Ignition OFF, disconnect the X1 harness connector at the A20 radio/HVAC control.
2. Ignition ON, test for greater than 10 V between the signal circuit terminal 5 and ground.

• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

3. If all circuits test normal, test or replace the A20 radio/HVAC control.

Child Security Door Lockout Inoperative
1. Ignition OFF, disconnect the X1 harness connector at the K9 BCM.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.

• If the test lamp does not illuminate and the B+ circuit fuse is normal, test the B+ circuit for an open/high resistance.
• If the test lamp does not illuminate and the B+ circuit fuse is open, test the B+ circuit for a short to ground.

3. Ignition OFF, connect the X1 harness connector and disconnect the X7 harness connector at the K9 BCM.
4. Connect a test lamp between the signal circuit terminal 12 and B+. Observe the test lamp while manually locking and unlocking the left rear door, the test lamp should turn ON and OFF while changing between the commanded states.

• If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit tests normal, test or replace the A23LR door latch assembly-left rear.

5. Connect a test lamp between the signal circuit terminal 18 and B+. Observe the test lamp while manually locking and unlocking the right rear door, the test lamp should turn ON and OFF while changing between the commanded states.

• If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit tests normal, test or replace the A23RR door latch assembly-right rear.

6. Ignition OFF, connect the X7 harness connector at the K9 BCM and disconnect the X2 harness connector at the X53 fuse block-rear
7. Test for less than 30 ohm between the ground circuit terminal 27 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

8. Connect a test lamp between the control circuit terminal 19 and ground. Command the child lockout latches to LOCK and UNLOCK with a scan tool, the test lamp should briefly illuminate while changing between the commanded states.

• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.

9. Connect a test lamp between the control circuit terminal 28 and the control circuit terminal 35. Command the child lockout latches to LOCK and UNLOCK with a scan tool, the test lamp should briefly illuminate while changing between the commanded states.

• If the test lamp is always OFF, test the control circuit terminal 28 for an open/high resistance.

10. If all circuits test normal, replace the X53 fuse block-rear.

Child Security Door Lockout Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate A23R door latch assembly-rear.
2. Test for less than 30 ohm between the ground circuit terminal listed below and ground:

* A23LR door latch assembly-left rear terminal 8
* A23RR door latch assembly-right rear terminal 3

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, test for greater than 10V between the signal circuit terminal listed below and ground.

* A23LR door latch assembly-left rear terminal 9
* A23RR door latch assembly-right rear terminal 4

• If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.

4. Connect a test lamp between the control circuit terminal 2 and the control circuit terminal 7.
5. Command the child lockout ON and OFF with a scan tool, the test lamp should briefly illuminate while changing between the commanded states.

• If the test lamp is always OFF, test either control circuit for an open/high resistance.

6. If all circuits test normal, test or replace the A23R door latch assembly-rear.

Lockout Indicator Malfunction
1. Ignition OFF, disconnect the X2 harness connector at the K9 BCM.
2. Ignition ON, verify that the lockout indicator is OFF.

• If the lockout indicator is ON, test the control circuit terminal 6 for a short to ground. If the circuit tests normal, replace the A20 radio/HVAC control.

3. Install a 3 A fused jumper wire between the control circuit terminal 6 and ground, verify that the lockout indicator is ON.

• If the lockout indicator is OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the A20 radio/HVAC control.

4. If all circuits test normal, replace the K9 BCM.

Component Testing

Rear Door Latch Assembly
1. Ignition OFF, disconnect the harness connector at the appropriate A23 door latch assembly - rear.
2. Install a 25 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 A23 door latch assembly - rear should perform the LOCK and UNLOCK functions.

• If the function does not perform as specified, replace the A23 door latch assembly - rear.

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 BCM and radio/HVAC control replacement, programming and setup