B2558

CIRCUIT DESCRIPTION
The interior lamps consist of the dome lamp, courtesy lamps and the rearview mirror reading lamps. Battery voltage for the interior lamps is supplied by the BCM through the inadvertent power control circuit. The BCM controls the interior lamps by supplying ground to the courtesy lamp low control circuit. If the courtesy lamp low control circuit becomes shorted to voltage, DTC B2558 sets.

CONDITIONS FOR RUNNING THE DTC
At least one of the following conditions must exist:
^ At least one door is open.
^ The interior lamps are commanded on by the BCM.

CONDITIONS FOR SETTING THE DTC
^ The interior lamps are commanded on by the BCM.
^ The interior lamp control circuit is shorted to battery positive voltage for 125 milliseconds.

ACTION TAKEN WHEN THE DTC SETS
^ DTC B2558 is stored in the BCM memory.
^ The BCM disables the interior lamp control output for the remainder of the ignition cycle.

CONDITIONS FOR CLEARING THE DTC
^ The conditions for setting the DTC are no longer present.
^ A history DTC clears after 100 malfunction free ignition cycles.
^ The BCM receives the clear code command from the scan tool.

DIAGNOSTIC AIDS
If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST DESCRIPTION

Steps 1-10:

The number below refers to the step number on the diagnostic table.
3. This step tests for an internally shorted IP dimmer switch.