What Does B2597 Mean?
This code indicates that the Body Control Module (BCM) has detected a malfunction in the electrical circuit controlling the headlamp aim output relay. This system is responsible for powering the automatic headlamp leveling motors that adjust beam height based on vehicle load and road conditions. The BCM detected either an open circuit, short circuit, excessive resistance, or relay failure preventing proper operation of the headlamp aiming system.
Common Causes
35%
Failed headlamp aim output relay with internal contact degradation or coil failure
30%
Damaged wiring harness or corroded connectors between BCM and headlamp aim relay or leveling motors
20%
Shorted or open circuit in headlamp leveling motor assembly causing relay overload
10%
Blown fuse or fusible link in headlamp aim circuit providing relay power
5%
Failed Body Control Module with damaged relay driver circuit
Diagnostic Steps
1
Step 1: Visually inspect the headlamp aim relay location in the fuse/relay box and verify proper seating. Check for signs of overheating, burnt contacts, or corrosion on relay terminals and socket.
2
Step 2: Using a digital multimeter, test the headlamp aim relay by checking coil resistance (typically 70-120 ohms) and verifying relay clicks when 12V is applied to control terminals. Test relay contacts for continuity when energized.
3
Step 3: With relay removed, use multimeter to verify BCM provides proper ground signal to relay control circuit when headlamp aim function is commanded. Check for battery voltage on relay power supply terminal with ignition on.
4
Step 4: Inspect wiring harness from relay to headlamp leveling motors for damage, chafing, or water intrusion. Check all connector pins for corrosion, backed-out terminals, or spread contacts. Test resistance of headlamp leveling motors (typically 8-15 ohms each).
5
Step 5: Monitor live data with scan tool while commanding headlamp aim system operation. Verify BCM shows proper voltage and current draw on relay output circuit (typically 2-5 amps depending on system).
6
Step 6: After repair, clear codes, perform headlamp aim initialization procedure per manufacturer specifications, and cycle system through full range of motion to verify proper operation and confirm code does not return.
Estimated Repair Cost
$125 - $650
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected a malfunction in the electrical circuit controlling the headlamp aim output relay. This system is responsible for powering the automatic headlamp leveling motors that adjust beam height based on vehicle load and road conditions. The...
The most common cause of B2597 (Headlamp Aim Output Relay Circuit Failure) is: Failed headlamp aim output relay with internal contact degradation or coil failure
Typical repair costs for B2597 range from $125 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive, but headlamp aim may be incorrect causing reduced visibility or glare to oncoming traffic. Repair should be completed within a reasonable timeframe to ensure proper headlamp alignment for optimal night driving safety.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2597 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Lighting System
Difficulty
Type
Generic (SAE)
Recommended Tools
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