Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Door Lock Switch Signal | B3270 or B3272 | 1, 2,3 | 1, 2,3 | -- |
Driver Door Lock Actuator Unlock Control | 2 | 2 | 2 | -- |
Door Lock Actuator Unlock Control | 3 | 3 | 3 | -- |
Door Lock Actuator Lock Control | 1 | 1 | 1 | -- |
Door Lock Switch Ground | -- | 1,2,3 | 1,2,3 | -- |
Center Console Fuse Block Ground | -- | B1349 | 1,2,3 | -- |
1. Door Locks Inoperative 2. Driver Door Unlock Inoperative 3. Door Unlock Inoperative |
Each door lock switch is wired to the body control module (BCM) through a common door lock signal circuit. The BCM supplies voltage through the door lock signal circuits to each door lock switch. When either door lock switch is operated, this supply voltage is pulled to ground, providing the BCM with the required lock or unlock signal. In order for the BCM to distinguish between a lock and unlock signal, the lock switch contains two separate paths for this voltage to flow to the body ground. When the switch is operated to the lock position, the supply voltage flows to ground through a 470 ohm resistor. When the switch is operated to the unlock position, the supply voltage flows to ground through a different part of the switch circuit, which has no resistor. The BCM then interprets the flow of voltage as a lock or unlock request and powers the door lock actuators to the appropriate lock or unlock position.
The body control module (BCM) powers the reversible door latch assemblies by providing battery positive voltage and ground to the appropriate lock and unlock control circuits of the latch assemblies. The Lock control circuits of the driver and passenger door latch assemblies are all connected together; however, the Unlock control circuits are connected in a slightly different way. While the unlock control circuits for the passenger door lock actuators are connected together, the driver door latch assembly has a separate unlock control circuit. The system is designed this way so that the keyless entry transmitter may be used to unlock only the driver door. Despite this difference, all of the lock actuators perform much the same way. When the door lock actuators are not active, all actuator Lock and Unlock control circuits are at ground potential within the BCM. Transitioning of the latch assemblies to the lock or unlocked position depends upon which control circuits receive voltage and which control circuits receive ground.
Door Lock/Indicator Schematics
Power Door Locks Description and Operation
⇒ | If the reading does not change, refer to Door Lock Switch Malfunction. |
⇒ | If the driver door does not unlock, refer to Door Lock Malfunction. |
⇒ | If one or more passenger doors do not unlock, refer to Door Lock Malfunction. |
⇒ | If one or more vehicle doors do not lock, refer to Door Lock Malfunction. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM. |
⇒ | 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. |
⇒ | 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. |
⇒ | 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. |
⇒ | If the test lamp remains OFF during either of the commands, test for a short to ground on either control circuit. If the circuits test normal, replace the BCM. |
⇒ | If not the specified value, replace the appropriate Door Lock switch. |
⇒ | If greater than the specified range, replace the appropriate Door Lock switch. |
⇒ | If greater or less than the specified range, replace the appropriate Door Lock switch. |
⇒ | If the function does not perform as specified, replace the appropriate Door Latch. |
⇒ | If the function does not perform as specified, replace the appropriate Door Latch. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming. |