What Does B2499 Mean?
B2499 indicates the Body Control Module (BCM) has detected a fault in the courtesy lamp output circuit. The BCM monitors the courtesy/interior lamp circuit and has identified an electrical failure such as an open circuit, short to ground, short to power, or excessive current draw. This code specifically points to a problem with the BCM's ability to properly control or detect feedback from the courtesy lamp system.
Common Causes
35%
Faulty courtesy lamp bulb or LED module causing excessive current draw or internal short circuit
30%
Damaged wiring harness or corroded connector between BCM and courtesy lamps creating open or short circuit
20%
Faulty door jamb switch or input circuit causing BCM to detect circuit anomaly
15%
Failed BCM output driver circuit or internal BCM fault
Diagnostic Steps
1
Step 1: Perform visual inspection of all courtesy lamps, check for burnt bulbs, damaged LED modules, melted lamp sockets, or evidence of water intrusion. Remove and inspect bulbs for internal shorts or incorrect wattage.
2
Step 2: Using a digital multimeter, check for battery voltage at the courtesy lamp power feed wire with lamps activated. Verify ground circuit continuity by measuring resistance to chassis ground (should be less than 1 ohm).
3
Step 3: Disconnect the courtesy lamp connector and measure resistance of the circuit from BCM connector to lamp connector. Check for short to ground (should read OL/infinite) and short to power (should read no voltage present with BCM disconnected).
4
Step 4: With BCM connected and ignition on, use multimeter to backprobe the BCM courtesy lamp output circuit while commanding lamp on via scan tool bi-directional controls. Verify BCM is providing proper switching voltage (typically 12V when activated).
5
Step 5: If all circuits test normal, substitute known-good courtesy lamp assembly to eliminate lamp module internal fault. Monitor for code recurrence after clearing codes and cycling lamps multiple times.
6
Step 6: If fault persists with all external components verified, suspect BCM internal driver failure. Check BCM connector for corrosion, bent pins, or water damage before condemning BCM.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
B2499 indicates the Body Control Module (BCM) has detected a fault in the courtesy lamp output circuit. The BCM monitors the courtesy/interior lamp circuit and has identified an electrical failure such as an open circuit, short to ground, short to power, or excessive current draw. This code specific...
The most common cause of B2499 (COURTESY LAMP OUTPUT Failure) is: Faulty courtesy lamp bulb or LED module causing excessive current draw or internal short circuit
Typical repair costs for B2499 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this only affects interior courtesy lighting functionality. Repair at convenience, though lack of interior lighting may create minor inconvenience during nighttime entry/exit and could obscure interior controls in darkness.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2499 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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