B2577
DTC B2577
CIRCUIT DESCRIPTION
The body control module (BCM) controls the headlamp relay. The BCM grounds the headlamp control circuit which energizes the headlamp relay.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B2577 Headlamp Control Circuit Low
CONDITIONS FOR RUNNING THE DTC
The BCM must not be commanding the headlamp relay to energize.
CONDITIONS FOR SETTING THE DTC
- The BCM detects a short to ground or open in the headlamp relay coil control circuit when the BCM is not trying to energize the headlamp relay.
- The condition above must be present for more than 0.3 seconds.
ACTION TAKEN WHEN THE DTC SETS
The BCM stores DTC B2577 in memory.
CONDITIONS FOR CLEARING THE DTC
- A current DTC B2577 will clear if the BCM no longer detect a short to ground or open in the headlamp relay coil control circuit.
- A history DTC B2577 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
DIAGNOSTIC AIDS
- If the DTC B2577 is a history DTC, the fault may be intermittent.
- The following conditions may cause an intermittent malfunction to occur:
- An intermittent short to ground or open in the headlamp relay control circuit
- The headlamp relay coil is intermittently shorted to ground or open internally.
- The BCM is intermittently shorted to ground or open internally.
TEST
