What Does B2571 Mean?
This code indicates the Body Control Module (BCM) has detected a short to ground condition in the left lamp outage detection circuit. The lamp outage signal circuit monitors bulb operation and reports when a lamp has failed; when this monitoring circuit is shorted to ground, the BCM cannot properly detect left-side lamp failures. This affects the vehicle's ability to alert the driver of burned-out bulbs on the left side of the vehicle.
Common Causes
45%
Damaged or chafed wiring harness in left fender, door jamb, or body panel areas causing wire insulation breakdown and grounding
30%
Faulty left lamp socket with internal short to ground or corroded contacts creating ground path
15%
Failed lamp outage module or integrated lighting control module with internal short circuit
10%
Water intrusion or corrosion in left lamp housing or connector causing short to vehicle ground
Diagnostic Steps
1
Step 1: Perform visual inspection of all left-side lamp assemblies (headlight, turn signal, tail light) for physical damage, water intrusion, or corroded connectors. Remove bulbs and inspect sockets for melted contacts or moisture.
2
Step 2: Disconnect the left lamp outage signal circuit connector at the BCM. Using a digital multimeter, measure resistance from the lamp outage signal wire to ground with all left lamps disconnected. Reading should be infinite (open circuit); anything below 10k ohms indicates a short.
3
Step 3: With lamp circuit still disconnected from BCM, reconnect individual left lamp assemblies one at a time while monitoring resistance to ground. Identify which specific lamp circuit causes the short when reconnected.
4
Step 4: Inspect the identified circuit's wiring harness from lamp to BCM, paying special attention to pinch points at body panels, door jambs, and frame rails. Look for wire insulation damage, melted wires, or improper routing touching metal surfaces.
5
Step 5: If wiring appears intact, substitute or test the suspect lamp socket assembly by temporarily connecting a known-good socket. If short clears, replace the faulty socket.
6
Step 6: After repairs, reconnect all components, clear the DTC, and verify proper lamp operation. Monitor for code recurrence by cycling all left lamps through multiple on/off cycles and checking for proper outage detection function.
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a short to ground condition in the left lamp outage detection circuit. The lamp outage signal circuit monitors bulb operation and reports when a lamp has failed; when this monitoring circuit is shorted to ground, the BCM cannot properly ...
The most common cause of B2571 (Left Lamp Outage Signal Circuit Short to Ground) is: Damaged or chafed wiring harness in left fender, door jamb, or body panel areas causing wire insulation breakdown and grounding
Typical repair costs for B2571 range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive, but lamp outage warning system for left-side lights will not function properly, preventing driver notification of burned-out bulbs. This creates a safety risk if actual lamp failures go unnoticed, potentially causing visibility issues or traffic violations. Repair within 1-2 weeks.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2571 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Body
System
Body Electrical System - Exterior Lighting
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
