B2472

DTC B2472 Low Beam Fault:

DTC B2472 Low Beam Fault (Part 1 Of 2):

DTC B2472 Low Beam Fault (Part 2 Of 2):

CIRCUIT DESCRIPTION
When the ignition is in the On position, the Body Control Module (BCM) supplies exterior lamp power to the high side of the low beam relay coil. When the BCM receives an input to turn the low beam lamps On, it grounds the coil which energizes the relay. This allows battery power to be supplied to the low beam lamps.

CONDITIONS FOR SETTING THE DTC
The BCM monitors the output to the low beam relay every second at terminal C9. The criteria for the fault code to set is as follows:
^ Exterior lamp power is active.
^ A DTC B1970 is not set.
^ Headlamp switch is inactive.
^ The commanded state doesn't match the feedback for 3 seconds (open circuit or short to ground).

ACTION TAKEN WHEN THE DTC SETS
1. The BCM continues to command the requested states until it is achieved or until it changes.
2. A DTC B2472 stores in the BCM memory.

CONDITIONS FOR CLEARING THE DTC
^ The conditions for the fault are no longer present.
^ The use of a scan tool.
^ A history DTC will clear after 50 ignition cycles if the condition for the fault is no longer present.

DIAGNOSTIC AIDS
^ Refer to Fuse Block Details for an end view and for terminal assignments of the relay box when the diagnostics directs you to take electrical measurements at the relay box.
^ 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.
^ A short to ground in CKT XA810 may cause the low beams to illuminate at all times with the ignition On and the headlamp switch in the Off position.

TEST DESCRIPTION
The following numbers refer to step numbers on the diagnostic table:
2. When the low beam relay is commanded On and 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. Check the BCM again after checking the voltage and ground inputs to see if the DTC resets indicating an internal failure.
7. The relay may be faulty if no circuit problems are verified. However, in most cases this is an unlikely failure.