• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Door Lock/Unlock Signal | 2 | 2 | 2 | -- |
Driver Door Lock Actuator Unlock Control | 1 | 1 | 1 | -- |
Door Lock Actuator Unlock Control | 1 | 1 | 1 | -- |
Door Lock Actuator Lock Control | 1 | 1 | 1 | -- |
Door Lock Switch Ground | -- | 2 | 2 | -- |
1. Door Lock Malfunction 2. Door Lock Switch Malfunction |
Each door lock switch is wired to the body control module (BCM) through a separate door lock/unlock signal circuit. While these circuits are separated between the BCM and respective door lock switch, they are connected into a single circuit within the BCM. The BCM supplies voltage through the door lock/unlock 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 same body ground. When the switch is operated to the unlock position, the supply voltage flows to ground through a 1.5K ohm resistor. When the switch is operated to the lock 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 BCM powers the reversible door latch assemblies by providing battery positive voltage and ground to the appropriate lock and unlock control circuits of the door 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 latch assemblies are connected together, the 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 lock actuators perform much the same way. When the door latch assemblies are not active, all actuator lock and unlock control circuits are at ground potential within the BCM. Transitioning of the lock actuators 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
Control Module References for scan tool information
⇒ | If the parameter does not change, refer to Door Lock Switch Malfunction. |
⇒ | If one or more vehicle doors do not LOCK or UNLOCK, 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 C 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. |
• | Driver door latch control circuit terminal 2 |
• | Driver door latch control circuit terminal 3 |
• | Left rear door latch control circuit terminal 2 |
• | Left rear door latch control circuit terminal 2 |
• | Passenger door latch control circuit terminal 5 |
• | Passenger door latch control circuit terminal 6 |
• | Right rear door latch control circuit terminal 5 |
• | Right rear door latch control circuit terminal 6 |
⇒ | If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. |
• | Driver door latch control circuit terminals 2 and 3 |
• | Left rear door latch control circuit terminals 2 and 3 |
• | Passenger door latch control circuit terminals 5 and 6 |
• | Right rear door latch control circuit terminals 5 and 6 |
⇒ | 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 door lock switch. |
⇒ | If greater than the specified range, replace the door lock switch. |
⇒ | If greater or less than the specified range, replace the door lock switch. |
• | Driver door latch control terminal 2 |
• | Left rear door latch control terminal 2 |
• | Passenger door control terminal 5 |
• | Right rear door control terminal 5 |
• | Driver door latch control terminal 3 |
• | Left rear door latch control terminal 3 |
• | Passenger door latch control terminal 6 |
• | Right rear door latch control terminal 6 |
⇒ | If the function does not perform as specified, replace the door latch. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |