• | 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 | -- |
Door Latch Control | 1 | 1 | 1 | -- |
BCM Ground | -- | 1 | 1 | -- |
Driver Door Lock Switch Ground | -- | 2 | 2 | -- |
Passenger Front Door Lock Switch Ground | -- | 2 | 2 | -- |
BCM Ground | -- | 1 | 1 | -- |
1. Door Lock Malfunction 2. Door Lock Switch Malfunction |
The dr lck fuse supplies battery positive voltage to the body control module (BCM) for the door lock system. The BCM supplies and monitors a reference voltage to the door lock switch through the door lock switch lock/unlock signal circuit. The door lock switch also receives a constant ground source. If a door lock switch is placed in the lock position, the reference voltage is taken directly to ground and the BCM detects the voltage on the signal circuit. If a door lock switch is placed in the unlock position, the reference voltage is taken to ground through a 1.5k ohm resistor that is internal to the door lock switches and detects approximately 2.9 volts on the signal circuit. This is how the BCM determines what portion of the door lock switch was activated. The BCM, upon receipt of a door lock switch lock or unlock signal, will switch the appropriate door lock actuator control circuits to battery positive voltage. The opposing side of the door lock actuators are connected to ground internally within the BCM through the other door lock actuator control circuit and the doors will lock or unlock appropriately. Vehicles without keyless entry have 2 internal drivers in the BCM to control the door lock actuators. All door lock and all door unlock. Vehicles equipped with keyless entry have 3 internal drivers in the BCM. Driver door unlock, passenger door unlock and all door lock. This is done to isolate the driver door lock actuator so it can be unlocked by itself using the keyless entry transmitter.
Door Lock/Indicator Schematics
Power Door Locks Description and Operation
Control Module References for scan tool information
⇒ | If the value does not change between the commanded states, refer to Door Lock Switch Malfunction. |
⇒ | If a door does not LOCK or UNLOCK when changing between the commanded states, refer to Door Lock Malfunction. |
⇒ | If all door latches are inoperative, refer to Door Latches Inoperative. |
⇒ | 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 the test lamp is always OFF, test either control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the BCM. |
⇒ | If the test lamp is always ON, test either control circuit for a short to voltage. If the circuits test normal, replace the BCM. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the driver door latch. |
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate door latch. |
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate door latch. |
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate door latch. |
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate door latch. |
⇒ | If less than the specified value, replace the door lock switch. |
⇒ | If greater than the specified value, replace the door lock switch. |
⇒ | If not within the specified range, replace the door lock switch. |
⇒ | If it 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 |
• | 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 | -- |
Door Latch Control | 1 | 1 | 1 | -- |
Driver Door Lock Switch Ground | -- | 2 | 2 | -- |
Passenger Front Door Lock Switch Ground | -- | 2 | 2 | -- |
Rear Door Lock Switch Ground | -- | 2 | 2 | -- |
BCM Ground | -- | 1 | 1 | -- |
1. Door Lock Malfunction 2. Door Lock Switch Malfunction |
The DR LCK fuse supplies battery positive voltage to the body control module (BCM) for the door lock system.
The BCM supplies and monitors a reference voltage to the door lock switch through the door lock switch lock/unlock signal circuit. The door lock switch also receives a constant ground source. If a door lock switch is placed in the lock position, the reference voltage is taken directly to ground and the BCM detects the voltage drop on the signal circuit. If a door lock switch is placed in the unlock position, the reference voltage is taken to ground through a 1.5k ohm resistor that is internal to the door lock switches and detects approximately 2.9 V on the signal circuit. This is how the BCM determines what portion of the door lock switch was activated.
The BCM, upon receipt of a door lock switch lock or unlock signal, will switch the appropriate door lock actuator control circuits to battery positive voltage. The opposing side of the door lock actuators is connected to ground internally within the BCM through the other door lock actuator control circuit and the doors will lock or unlock appropriately.
If either panel van access panels are open or ajar, the driver door will immediately UNLOCK following the LOCK command. If both access panels are closed and the scan tool Door Ajar Switch parameter is Door Ajar, refer to Door Ajar Indicator Malfunction
Door Lock/Indicator Schematics
Power Door Locks Description and Operation
Control Module References for scan tool information
⇒ | If the value does not change between commanded states, refer to Door Lock Switch Malfunction |
⇒ | If a door does not LOCK or UNLOCK when changing between the commanded states, refer to Door Lock Malfunction. |
⇒ | If both door latches are inoperative, refer to Door Latches Inoperative. |
⇒ | 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 the test lamp is always ON, test either control circuit for a short to voltage. If the circuits test normal, replace the BCM. |
⇒ | If the test lamp is OFF during the LOCK or UNLOCK command, test either control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the BCM. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the driver door latch. |
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate door latch. |
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the passenger door latch. |
⇒ | If not the specified value, replace the door lock switch. |
⇒ | If greater or less than the specified range, replace the door lock switch |
⇒ | If greater than the specified range, replace the door lock switch. |
⇒ | If it 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 |