Circuit Description
The outputs to the door lock actuators are controlled by the body control module (BCM). When the BCM receives a lock input from a door lock switch, or a keyless entry transmitter, it applies battery positive voltage to the door lock actuator lock control circuit, a ground to the door lock actuator unlock control, and the driver door lock actuator unlock control circuits. When the BCM receives an unlock input from a door lock switch, it applies battery positive voltage to the door lock actuator unlock control, the driver door lock actuator unlock control circuits, and a ground to the door lock actuator lock control circuit . When the BCM receives an single Unlock input from a keyless entry transmitter, it applies battery positive voltage to the driver door lock actuator unlock control circuit and a ground to the door lock actuator lock control circuit to unlock the driver door. A second Unlock input from the transmitter applies battery positive voltage to the door lock actuator unlock control circuit, and a ground to the door lock actuator lock control circuit to unlock the passenger doors.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B3128 Left Front/Driver Door Unlock Circuit High |
| • | DTC B3133 All Door Unlock Circuit High |
| • | DTC B3138 All Door Lock Circuit High |
Conditions for Setting the DTC
The BCM detects a short to voltage on the door lock actuator lock control circuit, door lock actuator unlock control circuit, or driver door lock actuator unlock control circuit for greater than 150 milliseconds.
Action Taken When the DTC Sets
| • | The BCM stores DTC B3128, B3133, or B3138 in memory. |
| • | The BCM disables the output function, Lock or Unlock, associated with the ground side circuit output. |
Conditions for Clearing the DTC
| • | A current DTC B3128, B3133, or B3138 is cleared when the BCM no longer detects a short to voltage on the door lock actuator lock control circuit, door lock actuator unlock control circuit, or driver door lock actuator unlock control circuit for greater than 150 milliseconds. |
| • | A history DTC B3128, B3133, or B3138 is cleared after 100 consecutive ignition cycles with the condition for setting the DTC no longer present. |
| • | The DTC is cleared using a scan tool. |
Diagnostic Aids
| • | If DTC B3128, B3133, or B3138 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
| • | The following conditions may cause an intermittent malfunction to occur: |
| - | An intermittent short to voltage on the door lock actuator lock control circuit, door lock actuator unlock control circuit, or driver door lock actuator unlock control circuit |
| - | The BCM intermittently shorted to voltage internally. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests to determine if the DTC is intermittent.
-
This step tests to determine if a lock or unlock circuit is malfunctioning.
-
This step tests to determine if the driver door unlock or all door unlock circuit is malfunctioning.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Door Lock/Indicator Schematics Connector End View Reference: Power Door Systems Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Are DTCs B3128, B3133, and B3138 Current DTCs? | Go to Step 3 | Go to Diagnostic Aids | |
Is the Lock function inoperative? | Go to Step 4 | Go to Step 7 | |
Is the Lock function inoperative on the driver door? | Go to Step 5 | Go to Step 6 | |
5 | Test the driver door lock actuator unlock control circuit for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 8 |
6 | Test the door lock actuator unlock control circuit for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 8 |
7 | Test the door lock actuator lock control circuit for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 8 |
8 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
9 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 2 | System OK |
