Park Lamp Relay Circuit Malfunction
The B2251 code indicates that the Body Control Module (BCM), Front Electronic Module (FEM), or Smart Junction Box (SJB) has detected a fault in the park lamp relay control circuit. This occurs when the module senses an incorrect voltage level on the relay driver, such as a short to ground, short to battery, or open circuit, preventing the relay from energizing properly. As a result, the front and rear parking lights may not illuminate or may operate intermittently, compromising vehicle visibility and compliance with lighting regulations.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty park lamp relay with damaged internal coil
- Short to ground or battery voltage in the relay control circuit wiring
- Open circuit, high resistance, or chafed wiring between the module and relay
- Corroded, loose, or damaged connectors or pins in the relay harness
3. Symptoms You Will Notice
- Parking lights do not turn on
- Parking lights operate intermittently or flicker
4. Step-by-Step Diagnosis
Check for blown fuses related to the park lamp circuit
Inspect the park lamp relay and its wiring for shorts, opens, or corrosion
Test the relay control circuit voltage at the module connector
Verify proper operation of the relay by swapping with a known good relay
If all else is normal, suspect internal module failure and perform module-specific diagnostics
5. Frequently Asked Questions
Is it safe to drive?▼
Driving with this code is not recommended because non-functional parking lights reduce your vehicle's visibility to other drivers, especially at night or in low-light conditions, and may violate local lighting laws.
How much does it cost to fix?▼
Repair costs typically range from $100 to $400, depending on whether the issue is a simple relay replacement ($20-$50) or requires module repair or replacement ($200-$400 or more).