For a full page schematic, refer to Door Lock/Indicator Schematics .
Circuit Description
The body control module (BCM) monitors and supplies an output voltage on CKT 194 to unlock the doors. When the BCM receives a UNLOCK signal from a door lock switch to UNLOCK the passenger door the BCM supplies voltage to the unlock relay and unlocks the door.
Conditions for Running the DTC
| • | The system voltage must be between 9.0 and 16.0 volts. |
| • | The door locks must be activated to LOCK/UNLOCK the doors. |
Conditions for Setting the DTC
| • | When CKT 194 is shorted to battery voltage for approximately 3 minutes. |
| • | The system voltage must be between 9.0 volts and 16.0 volts. |
Action Taken When the DTC Sets
The power door lock system will not function with either door switch.
Conditions for Clearing the MIL/DTC
| • | A current DTC will clear immediately after the short to battery voltage is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
| • | History and current DTC(s) can be cleared using a scan tool. |
Diagnostic Aids
| • | Always begin diagnosis with the first DTC listed on the scan tool. |
| • | The scan tool must display DTC B3148 as a current code before performing these diagnostics. |
| • | Perform a visual check for loose or poor connections at all related components. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
Listen for an audible click when the Unlock Relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
-
Verifies that the Body Control Module (BCM) is providing voltage to the Unlock Relay.
-
Tests for an open in the ground circuit to the Unlock Relay.
-
Tests if voltage is constantly being applied to the Unlock Relay.
-
After replacement of the BCM you must calibrate the new module for proper operation.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Power Door Systems Diagnostic System Check? | -- | Go to Step 2 | |
Does the unlock relay turn ON and OFF with each command? | -- | Go to Testing for Intermittent Conditions and Poor Connections | 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 unlock relay for a short to ground. 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 unlock relay 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 unlock relay . 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 unlock relay . Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 13 | -- |
11 | Replace the unlock relay . Did you complete the replacement? | -- | Go to Step 13 | -- |
Did you complete the replacement? | -- | Go to Step 13 | -- | |
13 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
