Refer to
Automatic Headlamp Control Module, Ambient Light Sensor and BCM
.
Circuit Description
The BCM interfaces with the DRL control module through automatic headlamp link circuit to determine the ambient light operation mode. The BCM communicates this information to the instrument cluster through the Class II serial data link.
Conditions for Setting the DTC
The BCM detects a short to ground or an open in the automatic headlamp link circuit when turning the ignition switch from START to ON.
Action Taken When the DTC Sets
The BCM stores DTC B2603 in memory.
Conditions for Clearing the DTC
| • | When the ignition switch is turned from OFF to ON, a current DTC B2603 is always cleared. If a short to ground or open is still present when the ignition switch is turned from START to ON, DTC B2603 will reset as a current DTC. |
| • | 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 the automatic headlamp link circuit. |
| - | The automatic headlamp control module is shorted to B+. |
| - | The BCM is short to B+. |
| • | If the DTC is a history DTC, the problem may be intermittent. Try performing the tests shown while moving the wiring and connectors, this can often cause the malfunction to reappear. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for voltage in automatic headlamp link circuit.
-
This step tests for a short to B+ in the automatic headlamp circuit.
-
This step tests for a short to B+ in the automatic headlamp control module
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | ||
Is the test light ON? | -- | |||
Inspect for a short to B+ in the automatic headlamp link circuit Is a short to B+ in the circuit? | -- | |||
4 | Repair short to B+ in the automatic headlamp link circuit. Is the repair complete? | -- | -- | |
Does the test lamp illuminate? | -- | |||
6 | Replace the automatic headlamp control module. Refer to Headlamp Control Module Replacement . Has the repair been made? | -- | -- | |
7 | Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Is the repair complete? | -- | -- | |
8 |
Are any current DTCs set? | -- | System OK |
