Circuit Description
The body control module (BCM) controls the interior illumination. The BCM turns ON the roof rail courtesy/reading lamps and the inside rear view mirror lamps under the following conditions:
| • | Any vehicle door is opened. |
| • | The IP dimmer switch is in the DOME position. |
| • | During exit illumination or delayed illumination |
| • | Lifting either the left front or the right front door handle |
| • | When unlocking the doors using the keyless entry transmitter |
The BCM turns off the lamps when all doors are closed and the IP dimmer switch is off.
All vehicle doors contain a door lock ajar switch. When the driver's door is open, the left front door lock ajar switch closes and sends a ground signal to the BCM through circuit 49. When the left front, right front, left rear, or right rear door is open, the corresponding door lock ajar switch closes and sends a ground signal to the BCM through circuit 727. The left front and the right front door locks have a door handle switch. When either the left front or the right front door handle is lifted, the corresponding door lock switch sends a ground signal to the BCM through circuit 394. The BCM grounds circuit 157 when detecting a ground signal in circuit 49, circuit 394, or circuit 727.
When the driver's door is closed, the left front door lock ajar switch opens circuit 49. When the left front, right front, left rear, and right rear doors are closed, the corresponding door lock ajar switches open circuit 727. When the left front and the right front door handles are released, circuit 394 opens. The BCM then opens circuit 157 when circuit 49, circuit 394, and circuit 727 are open.
The BCM uses the voltage in circuit 240 in order to power the courtesy lights through circuit 1732. The BCM controls the power supplied in circuit 1732 for inadvertent load (battery rundown) protection. The BCM opens circuits 157 when the inadvertent load (battery rundown) protection is active (circuit 1732 is open).
Conditions for Setting the DTC
The BCM detects a short to B+ in circuit 157 for more than 0.15 seconds.
Action Taken When the DTC Sets
The BCM stores DTC B2618 in memory.
Conditions for Clearing the DTC
| • | A short to B+ is no longer detected by the BCM in circuit 157. |
| • | A history DTC will clear after 100 consecutive ignition cycles if the condition for the fault is no longer present. |
| • | Using a scan tool |
Diagnostic Aids
| • | The following conditions may cause an intermittent malfunction to occur: |
| - | An intermittent short to B+ in circuit 157 |
| - | The BCM is shorted to B+ internally. |
| • | If the DTC is a history DTC, the condition may be intermittent. Perform the tests shown while wiggling wiring and connectors. This may often cause the malfunction to reappear. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for a short to B+ in circuit 157.
-
This step determines whether the malfunction is intermittent or the BCM is faulty.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Lighting Systems in Body Control System |
2 | Inspect for current DTCs. Is DTC B2559 set also? | -- | Go to Step 3 | |
Is the voltage measured less than the specified value? | 2V | Go to Step 4 | Go to Step 5 | |
Does DTC B2618 reset as a current DTC? | -- | Go to Step 6 | Go to Step 7 | |
5 | Repair a short to B+ in circuit 157. Is the repair complete? | -- | Go to Step 8 | -- |
6 | Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Is the repair complete? | -- | Go to Step 8 | -- |
7 | The malfunction is not present at this time. Refer to Diagnostic Aids for additional information regarding this DTC. Is the repair complete? | -- | Go to Step 8 | -- |
8 |
Are any current DTCs set? | -- | Go to Diagnostic System Check - Lighting Systems in Body Control System | System OK |
