Circuit Description
The body control module (BCM) supplies battery positive voltage to the reading lamps, instrument panel (I/P) compartment lamp, and both visor vanity mirror lamps. In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent supply voltage circuit to prevent a total battery discharge condition.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1480 Battery Rundown Protection Circuit
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
| • | The inadvertent power supply voltage circuit to the reading lamps, I/P compartment lamp, and both visor vanity mirror lamps is shorted to ground for more than one second. |
| • | There is a loss of the rear fuse block TBC 4 battery supply voltage to the BCM for more than one second while one or more of the lamps in the inadvertent power supply voltage circuit have been activated. |
Action Taken When the DTC Sets
The reading lamps, I/P compartment lamp, and both visor vanity mirror lamps will not operate.
Conditions for Clearing the MIL/DTC
| • | This DTC will clear on current status after the condition for setting the fault is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
| • | History and current DTCs can be cleared using a scan tool. |
Diagnostic Aids
Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This test determines if an open or short to ground exists.
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This test determines if a short to ground exists in the lamp wiring or internally within the BCM.
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This test determines if an open exists in the TBC 4 battery positive voltage circuit, the inadvertent power supply voltage circuit, or internally within the BCM.
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After replacement of the BCM you must calibrate the new module for proper operation.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Interior Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Computer/Integrating Systems Connector End Views in Computer/Integrating Systems | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Inspect the TBC 4 fuse in the rear fuse block. Is the fuse good? | Go to Step 4 | Go to Step 3 | |
Test the TBC 4 battery positive voltage and inadvertent power supply voltage circuits 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 7 | Go to Step 5 | |
Test the TBC 4 battery positive voltage and inadvertent power supply voltage circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 7 | Go to Step 5 | |
5 | Inspect for poor connections at the harness connectors 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 7 | Go to Step 6 |
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 7 | -- | |
7 |
Does the DTC reset? | Go to Step 2 | System OK |
