What Does B2555 Mean?
This code indicates the Body Control Module (BCM) has detected that the dome lamp output circuit is shorted directly to battery voltage when it should not be. The BCM monitors the dome lamp circuit and has determined there is an unintended power supply feeding the circuit, likely causing the dome lamp to stay on continuously or preventing proper control. This typically means the output wire from the BCM to the dome lamp has contacted a power source somewhere in the circuit.
Common Causes
45%
Damaged or chafed wiring harness causing the dome lamp circuit wire to contact a power wire or pin in a connector
30%
Faulty dome lamp assembly with internal short circuit connecting power directly to control circuit
15%
Shorted door jamb switch or courtesy lamp switch feeding voltage back through the circuit
10%
Failed Body Control Module with internal driver circuit failure causing false short detection or actual internal short
Diagnostic Steps
1
Step 1: Disconnect the dome lamp assembly connector(s) and check if the fault clears. Use a multimeter to measure voltage at the BCM output wire at the lamp connector with lamp disconnected - should read 0V when off, battery voltage when commanded on.
2
Step 2: If voltage is present at the disconnected lamp connector when dome lamp should be off, trace the dome lamp circuit wiring from BCM to lamp checking for chafed insulation, pinched wires at body seams, or damaged connectors that could be contacting power circuits.
3
Step 3: With dome lamp still disconnected, disconnect door jamb switches and any other courtesy lamp switches one at a time to determine if a faulty switch is back-feeding voltage into the circuit.
4
Step 4: Inspect the dome lamp assembly for water intrusion, corrosion, or visible damage. If assembly appears damaged, replace and verify proper operation. Check for aftermarket accessories or alarm systems spliced into dome lamp circuit.
5
Step 5: If all wiring and components test normal, perform BCM output circuit test per manufacturer procedures using a test light or load resistor to verify BCM can properly control ground side switching without detecting a short.
6
Step 6: Clear codes, operate all dome lamp functions (door open, manual switch, timer functions), and verify proper operation without code return. Monitor live data for dome lamp circuit status during testing.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected that the dome lamp output circuit is shorted directly to battery voltage when it should not be. The BCM monitors the dome lamp circuit and has determined there is an unintended power supply feeding the circuit, likely causing the dome la...
The most common cause of B2555 (LAMP DOME OUTPUT Circuit Short to Battery) is: Damaged or chafed wiring harness causing the dome lamp circuit wire to contact a power wire or pin in a connector
Typical repair costs for B2555 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 affects only interior lighting functionality. Primary concern is potential battery drain if dome lamp stays on continuously and possible distraction from unwanted interior lighting while driving at night.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2555 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
Interior Lighting System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
