Circuit Description
The body control module (BCM) uses the courtesy lamps supply voltage circuit as a input circuit and a output circuit. When used as an output circuit the BCM provides battery power to the courtesy lamps. When used as a input circuit the BCM provides an interface to the electrical loads which are controlled by the BCM when the output is inactive. This will allow for determination of the ON/OFF status of the loads.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1482 Battery Rundown Protection Circuit Low
Conditions for Running the DTC
If the voltage level at the BCM drops to 0.
Conditions for Setting the DTC
| • | The fault code sets when the BCM commanded state does not match the feedback. When the courtesy lamps supply voltage circuit is commanded high and a short to ground is present. |
| • | The fault code also sets when the battery positive voltage circuit of the BCM that is fed by the Accy Pwr Bus fuse is open or shorted to ground. |
| • | The condition above must be present for more than 0.1 seconds. |
Action Taken When the DTC Sets
The BCM stores DTC B1482 in memory.
Conditions for Clearing the MIL/DTC
| • | A current DTC B1482 will clear if voltage is present on the battery positive voltage circuit and the BCM does not detect a short to ground. |
| • | A history DTC B1482 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present nor any other malfunction in the BCM is detected. |
| • | The BCM receives a clear code command from the scan tool. |
Diagnostic Aids
| • | If the DTC B1482 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 ground in the courtesy lamps supply voltage circuit . |
| - | An intermittent open in the battery positive voltage circuit of the BCM that is fed by the Accy Pwr Bus fuse. |
| - | The BCM is intermittently shorted to ground. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Interior Lights Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool display ON? | Go to Diagnostic Aids | Go to Step 3 |
3 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 6 |
4 |
Do the reading lamps operate? | Go to Step 5 | Go to Step 7 |
5 | 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 9 | Go to Step 8 |
6 | Repair an open or short to ground in the battery positive voltage circuit of the BCM that is fed by the Accy Pwr Bus fuse. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
7 | Repair an open or a short to ground in the courtesy lamps supply voltage circuit of the BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
8 | 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 9 | -- |
9 |
Does the DTC reset? | Go to Step 2 | System OK |
