B2577

DTC B2577

CIRCUIT DESCRIPTION
The body control module (BCM) controls the automatic headlamp relay through the headlamp relay control circuit. The BCM grounds the automatic headlamp relay control circuit energizing the headlamp relay.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
TC 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 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 detects a short to ground or open in the automatic headlamp relay control circuit.
- A history DTC B2577 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
- The BCM receives a clear code command from the scan tool.

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 automatic headlamp relay control circuit.
- The headlamp relay coil is intermittently shorted to ground or open.
- The BCM is intermittently shorted to ground or open.

TEST

Steps 1 - 14:

Step 15: