B2571: Left Lamp Monitor Circuit Short to Ground
The B2571 code indicates that the Body Control Module (BCM) or Front Electronic Module (FEM) has detected a short to ground in the left lamp feedback or monitor circuit. This circuit is responsible for monitoring the operational status of the left lamp to detect if the bulb is burned out or disconnected. A short to ground in the signal wiring causes an abnormal voltage reading, leading the module to register a fault in the lamp monitoring system.
1. Commonly Affected Makes
2. Most Common Causes
- Short to ground in the left lamp signal circuit wiring
- Corroded, damaged, or shorted pins in the lamp connector or socket
- Defective lamp with abnormal internal resistance or filament shorted to ground
- Internal failure of the Body Control Module (BCM) or Front Electronic Module (FEM)
3. Symptoms You Will Notice
- Left lamp may not illuminate or may flicker
- Warning light on the dashboard indicating a lamp failure
4. Step-by-Step Diagnosis
Visually inspect the left lamp bulb and socket for corrosion, damage, or debris
Check the wiring and connector for signs of short to ground using a multimeter
Test the lamp bulb resistance and compare to specifications
If wiring and bulb are okay, suspect a faulty BCM or FEM and perform module diagnostics
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, it is generally safe to drive, but the affected lamp may not work properly, reducing visibility and safety. It is recommended to repair the issue promptly.
How much does it cost to fix?▼
Repair costs typically range from $100 to $300, depending on whether the issue is a simple bulb replacement, wiring repair, or module replacement.