When the body control module (BCM) detects a transition of either of the door lock switches to the lock position, it switches the door lock actuator lock control circuit to voltage. Since the lock actuator unlock control circuits are at ground potential within the BCM, the door lock actuator motors transition to the Lock position. When the BCM detects a transition of either of the door lock switches to the unlock position, it switches the driver door lock actuator unlock control circuit to voltage. Since the door lock actuator lock control circuit is at ground potential within the BCM, the LF door lock actuator motor transitions to the unlock position. The driver door lock actuator unlock control circuit is a dedicated control circuit used only for the driver door lock actuator motor. This is done so that the driver door may be unlocked by itself using a keyless entry transmitter or an automatic door unlock function, if programmed. The passenger doors include the passenger front door, the passenger rear sliding doors, and the liftgate door. When the BCM detects a transition of either of the door lock switches to the unlock position, it switches the door lock actuator unlock control circuits to voltage. Since the door lock actuator lock control circuit is at ground potential within the BCM, the passenger door lock actuator motors transition to the unlock position. The door lock actuator unlock control circuits are dedicated control circuits used only for the passenger door lock actuator motors. This is done so that the driver door may be unlocked separately from the passenger doors using a keyless entry transmitter or an automatic door unlock function, if programmed.

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Power Door Systems Connector End Views

Description and Operation

Power Door Locks Description and Operation

Electrical Information Reference

Scan Tool Reference

1. Ignition ON, observe the scan tool LF Door Lock Switch, parameters while using the driver door lock switch. The parameters should change between Idle, Lock and Unlock.

⇒	If the value does not change, refer to Driver Door Lock Switch Malfunction.

2. Observe the scan tool RF Door Lock Switch and RF Door Unlock Switch parameters while using the passenger door lock switch. The parameters should change between Active and Inactive.

⇒	If the value does not change, refer to Passenger Door Lock Switch Malfunction.

3. Command the doors and liftgate to LOCK and UNLOCK with a scan tool. All the doors and the liftgate should perform the LOCK and UNLOCK function.

⇒	If the driver door, passenger door or liftgate does not perform as specified, refer to Front Door/Liftgate Lock Malfunction.

⇒	If either sliding door does not perform as specified, refer to Sliding Door Lock Malfunction.

Driver Door Lock Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the driver door lock switch.
2. Test for less than 1 ohm between the ground circuit terminal C and ground.

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

3. Ignition ON, verify the scan tool LF Door Lock Switch parameter is Idle.

⇒	If not the specified value, test the signal circuit terminal D or signal circuit terminal E for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool LF Door Lock Switch parameter is Unlock.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

5. Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool LF Door Lock Switch parameter is Lock.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

6. If all circuits test normal, test or replace the driver door lock switch.

Passenger Door Lock Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the passenger door lock switch.
2. Test for less than 1 ohm between the ground circuit terminal C and ground.

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

3. Ignition ON, verify the scan tool RF Door Lock Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the BCM.

4. Verify the scan tool RF Door Unlock Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the BCM.

5. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool RF Door Unlock Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

6. Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool RF Door Lock Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

7. If all circuits test normal, test or replace the passenger door lock switch.

Front Door/Liftgate Lock Malfunction

1. Ignition OFF, disconnect the C2 harness connector at the BCM.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 49 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

3. Ignition OFF, connect the C2 harness connector at the BCM and disconnect the harness connector at the appropriate door latch assembly.
4. Test for less than 1 ohm between the control circuit terminal B and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the BCM.

5. Test for less than 1 ohm between the control circuit terminal A and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the BCM.

6. Connect a test lamp between control circuit terminal B and control circuit terminal A.
7. Ignition ON, command the door latch assembly to LOCK and UNLOCK by using the door lock switch. The test lamp should briefly illuminate during the LOCK and UNLOCK command.

⇒	If the test lamp remains OFF during either of the commands, test either control circuit for a short to ground. If the circuits test normal, replace the BCM.

8. If all circuits test normal, test or replace the door latch assembly.

Sliding Door Lock Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate door contact plate.
2. Test for less than 1 ohm between the control circuit terminal B and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If all circuits test normal, replace the BCM.

3. Test for less than 1 ohm between the control circuit terminal A and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If all circuits test normal, replace the BCM.

4. Connect a test lamp between control circuit terminal B and control circuit terminal A.
5. Ignition ON, command the door latch to LOCK and UNLOCK with a scan tool. The test lamp should briefly illuminate during the LOCK and UNLOCK command.

⇒	If the test lamp remains OFF during either of the commands, test either control circuit for a short to ground. If the circuits test normal, replace the BCM.

6. Ignition OFF, connect the harness connector at the door contact plate and close the sliding door.
7. Disconnect the harness connector at the door lock actuator.
8. Test for less than 1 ohm between the control circuit terminal B and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the door contact plate.

9. Test for less than 1 ohm between the control circuit terminal A and ground.

⇒	If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the door contact plate.

10. Connect a test lamp between control circuit terminal B and control circuit terminal A.
11. Ignition ON, command the door latch to LOCK and UNLOCK with a scan tool. The test lamp should briefly illuminate during the LOCK and UNLOCK command.

⇒	If the test lamp remains OFF during either of the commands, test either control circuit for a short to ground. If the circuit tests normal, replace the door contact plate.

12. If all circuits test normal, test or replace the door lock actuator.

Door Lock Switch

1. Ignition OFF, disconnect the harness connector at the appropriate door lock switch.
2. Test for infinite resistance between the signal terminal E and the ground terminal C with the switch in the open position.

⇒	If not the specified value, replace the door lock switch.

3. Test for infinite resistance between the signal terminal D and the ground terminal C with the switch in the open position.

⇒	If not the specified value, replace the door lock switch.

4. Test for less than 2 ohms between the signal terminal E and the ground terminal C with the switch in the unlock position.

⇒	If greater than the specified range, replace the door lock switch.

5. Test for less than 2 ohms between the signal terminal D and the ground terminal C with the switch in the lock position.

⇒	If greater than the specified range, replace the door lock switch.

Door/Liftgate Latch

1. Disconnect the harness connector at the appropriate door latch.
2. Install a 25A fused jumper wire between the control terminal A and 12 volts. Momentarily install a jumper wire between the control terminal B and ground. The door latch should perform the LOCK/UNLOCK function

⇒	If the function does not perform as specified, replace the door latch.

3. Reverse the jumper wires; the door latch should perform the UNLOCK/LOCK function.

⇒	If the function does not perform as specified, replace the door latch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.