Circuit Description
The body control module (BCM) internally grounds the liftgate lock relay control circuit for the liftgate lock relay when it receives a class 2 message from the driver door module (DDM), passenger door module (PDM), or when a liftgate lock function is activated. When the BCM grounds the liftgate lock relay control circuit the liftgate lock relay is energized and locks the liftgate.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3825 Liftgate Lock Signal Circuit
Conditions for Running the DTC
| • | Battery voltage is between 9-16 volts. |
| • | The DTC will set if the liftgate lock function is active or inactive. |
Conditions for Setting the DTC
The DTC will set if the liftgate lock relay control circuit is shorted to ground or open for more then one second.
Action Taken When the DTC Sets
| • | If a short to ground is present on the liftgate lock relay control circuit, the liftgate lock relay will be energized and the liftgate lock actuator will be held in the lock position and will not unlock. |
| • | If an open condition is present on the liftgate lock relay control circuit, the liftgate will unlock but not lock. |
| • | The BCM will send a class 2 message to the DIC indicating that a fault has been detected and the DIC will display REPLACE LIFTGATE FUSE. |
Conditions for Clearing the DTC
When the fault is no longer present, the BCM changes the current DTC to a history DTC. The BCM will clear the history DTC after 50 fault free ignition cycles.
Diagnostic Aids
DTC B3825 will set as current if any of the following conditions are present:
| • | An open ECC fuse |
| • | An open or short to ground in the liftgate lock relay battery positive voltage circuit |
| • | A faulty liftgate lock relay |
| • | An open or short to ground in the liftgate lock relay control circuit |
| • | A short to ground in the liftgate lock actuator lock control circuit will open the electronic climate control (ECC) with a lock command |
| • | A faulty BCM |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Command both the Lock and Unlock states. Repeat the commands as necessary.
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Tests for voltage at the coil side of the liftgate lock relay. The ECC fuse supplies power to the coil side of the liftgate lock relay.
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Verifies that the body control module is providing ground to the liftgate lock relay.
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Tests if ground is constantly being applied to the liftgate lock relay.
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 |
Does the liftgate Lock and Unlock with each command? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 8 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 9 | Go to Step 5 | |
Does the test lamp remain illuminated without being commanded? | Go to Step 7 | Go to Step 6 | |
6 | Test the liftgate lock relay control circuit of the liftgate lock relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
7 | Test the liftgate lock relay control circuit of the liftgate lock relay 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 14 | Go to Step 10 |
8 | Test for an open or short to ground in the battery positive voltage circuit of the liftgate lock relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | Go to Step 11 |
9 | Inspect for poor connections at the liftgate lock 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 12 |
10 | 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 14 | Go to Step 13 |
11 | Repair the short to ground in the liftgate lock actuator lock control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | -- |
12 | Replace the liftgate lock relay. Did you complete the replacement? | Go to Step 14 | -- |
13 | 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 14 | -- |
14 |
Does the DTC reset? | Go to Step 2 | System OK |
