DTC B1971, Inadvertent Power Fault: Notes

If interior lights are accidentally left on, a Delayed Interior Lighting (DIL) feature provides automatic shutoff. When ignition switch is in RUN position, BCM continuously keeps output to DIL relay active. When ignition switch is turned to OFF position, BCM will deactivate DIL relay output after 10 minutes. When ignition switch is turned to LOCK position, 10-minute timeout period resets anytime BCM wakes up and any of the following states are detected:

Illuminated Entry - A door is opened or closed; or driver door unlock message is received.
The trunk is opened or closed.
Interior lights are turned on.

When DIL relay is energized, power is supplied to interior lights and high side of interior light relay coil.

BCM continuously monitors output to DIL relay. DTC B1971 will set when output is commanded on or off, and short or open is detected for at least 2 seconds. When DTC B1971 is set, BCM will continue to command requested state of relay until it is achieved or no longer necessary. DTC B1971 will clear when BCM feedback state matches commanded state for at least 2 seconds or when scan tool is used.

NOTE: If DTC B1971 is a history code, problem may be intermittent. Wiggle wires while performing the following test.