B1971

DTC B1971 Inadvertent Power:

DTC B1971 Inadvertent Power (Part 1 Of 2):

DTC B1971 Inadvertent Power (Part 2 Of 2):

CIRCUIT DESCRIPTION
The delayed interior lighting (DIL) feature, a battery guard for the courtesy lamps, provides automatic shutoff of all the interior lamps if they are accidentally left On (inadvertent power).

The Body Control Module (BCM) deactivates the output to the DIL relay when any of the following occurs:
^ 10 minutes after the ignition switch transitions from On to Off.
^ The ignition switch is in the Start position.

The 10 minute time-out period resets anytime the BCM wakes up and any of the following states are detected:
1. Illuminated Entry i.e.
1.1. A door is opened or closed.
1.2. A RFA Class 2 message is received (driver door unlock).
1.3. An input (unlock) from the drivers door lock switch.
2. The trunk lid is opened or closed.
3. The interior lights are turned On from the headlamp switch.

The BCM continues to energize the DIL relay when the ignition switch is in the On position. No time-out period occurs in this position. When the DIL relay is energized it supplies power to the interior lights and the high side of the interior lamp relay coil.

CONDITIONS FOR SETTING THE DTC
The BCM monitors the output to the DIL relay every second at terminal C3. The fault code sets when the commanded state doesn't match the feedback for 2 seconds (open circuit, short to B+ or ground).

ACTION TAKEN WHEN THE DTC SETS
^ The BCM continues to command the requested state of the relay until it is achieved or is no longer necessary.
^ Stores a DTC B1971 in the BCM memory.

CONDITIONS FOR CLEARING THE DTC
^ The conditions for the fault are not longer present.
^ The use of the scan tool.
^ A history DTC will clear after 50 consecutive ignition cycles if the condition for the fault is no longer present.

DIAGNOSTIC AIDS
The problem may be intermittent if the DTC is a history DTC. Try performing the tests shown while wiggling the wiring and the connectors. Wiggling the wiring and the connectors can often cause the malfunction to appear. Refer to Intermittents and Poor Connections. Intermittents and Poor Connections

TEST DESCRIPTION
The following numbers refer to the step numbers on the diagnostic table:
2. When the DIL relay is commanded On/Off the status should match the commanded state. In most cases a no change in status indicates a circuit problem.
3. This test checks for proper voltage and ground input to the BCM. After checking these inputs, the BCM is checked again to see if the DTC resets indicating an internal failure.
4. This test measures the resistance of the relay coil. An open coil winding sets this DTC. The DIL relay is contained in the multifunction relay and cannot be serviced separately.