Circuit Description
The remote keyless entry keyfob sends a radio signal to the body control module (BCM) to unlock the driver door when the keyfob is pressed once. When the BCM receives the unlock driver door signal, the BCM applies battery voltage to the driver door lock/unlock motor.
Conditions for Running the DTC
The remote keyless entry keyfob is pressed once to unlock the driver door.
Conditions for Setting the DTC
| • | The BCM receives the unlock signal from the keyfob. |
| • | The driver door lock/unlock motor control circuit is shorted to ground for 250 milliseconds. |
Action Taken When the DTC Sets
The BCM disables the driver door lock/unlock motor control for the remainder of the ignition cycle. The door mounted switch will still operate properly.
Conditions for Clearing the DTC
| • | A current DTC B3127 will clear when the malfunction is no longer present and the ignition switch is cycled. |
| • | All BCM history codes clear after 100 ignition cycles with no current codes active during the 100 ignition cycles. |
Diagnostic Aids
| • | If the driver door unlock control circuit is open, the keyfob will be unable to unlock the driver door, but the door mounted switch will operate properly. |
| • | Pressing the keyfob switch while the driver door control circuit is shorted to ground is a direct short to battery and will blow the RFA BATT fuse. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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Listen for an audible click when the driver door unlock solenoid operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Verifies that the BCM is providing voltage to the driver door unlock solenoid.
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Tests for an open in the ground circuit to the driver door unlock solenoid.
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Tests if voltage is constantly being applied to the driver door unlock solenoid.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Door Systems Diagnostic System Check? | Go to Step 2 | |
Does the driver door unlock motor turn ON and OFF with each command? | Go to Diagnostic Aids | Go to Step 3 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 4 | Go to Step 5 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 8 | Go to Step 10 | |
Does the test lamp remain illuminated with each command? | Go to Step 7 | Go to Step 6 | |
6 | Test the control circuit of the driver door unlock motor for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
7 | Test the control circuit of the driver door unlock motor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
8 | Inspect for poor connections at the driver door unlock motor. 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 13 | Go to Step 11 |
9 | Inspect for poor connections at the harness connector of the 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 13 | Go to Step 12 |
10 | Repair the ground circuit of the driver door unlock motor. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | -- |
11 | Replace the driver door lock/unlock motor. Did you complete the replacement? | Go to Step 13 | -- |
12 |
Important: Perform the setup procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration . Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 13 | -- |
13 |
Does the DTC reset? | Go to Step 2 | System OK |
