What Does B2491 Mean?
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected a short to battery voltage in the right front park lamp output circuit. The BCM is seeing constant battery voltage on the circuit that controls the RF park lamp, even when the lamp should be off. This typically means the output wire is contacting a power source somewhere between the BCM and the lamp assembly.
Common Causes
45%
Damaged or chafed wiring harness between BCM and RF park lamp causing short to B+ voltage
25%
Failed park lamp socket with internal short to power circuit
20%
Water intrusion or corrosion in RF lamp assembly causing cross-circuit short
10%
Failed Body Control Module with internal driver circuit failure
Diagnostic Steps
1
Step 1: Perform visual inspection of RF park lamp assembly, socket, and visible wiring for obvious damage, melting, corrosion, or chafing against metal components. Check for water intrusion in lamp housing.
2
Step 2: Disconnect the RF park lamp connector at the lamp assembly. Clear the code and observe if it returns immediately. If code clears and stays cleared, the fault is in the lamp assembly or socket.
3
Step 3: With lamp disconnected and ignition on, use a digital multimeter to measure voltage at the BCM output connector terminal for RF park lamp circuit. Should read 0V with lamps off. If battery voltage present, wiring harness has short to power.
4
Step 4: Perform resistance test on the park lamp output circuit from BCM connector to lamp connector (both disconnected). Should read open circuit to ground and to B+ voltage. Low resistance to B+ confirms short location in harness.
5
Step 5: Trace and inspect the wiring harness routing from BCM to RF lamp, paying special attention to areas where harness passes through grommets, near sharp edges, or contacts body panels. Use a wire schematic to identify splice points.
6
Step 6: After repairing wiring or replacing faulty component, reconnect all connections, clear codes, cycle park lamps on/off multiple times, and verify code does not return. Test in various conditions including engine running.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected a short to battery voltage in the right front park lamp output circuit. The BCM is seeing constant battery voltage on the circuit that controls the RF park lamp, even when the lamp should be off. This typically me...
The most common cause of B2491 (RF PARK LAMP OUTPUT CIRCUIT Short to Battery) is: Damaged or chafed wiring harness between BCM and RF park lamp causing short to B+ voltage
Typical repair costs for B2491 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive during daylight hours, but reduced visibility to other drivers at night or in low-light conditions creates safety concern. Repair should be completed before regular nighttime driving to maintain proper vehicle lighting and legal compliance.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2491 to identify the root cause.
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Quick Info
Category
Body
System
Exterior Lighting System
Difficulty
Type
Generic (SAE)
Recommended Tools
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