What Does U1220 Mean?
Communication fault on SCP J1850 network regarding interior lamp outage detection data. A module responsible for monitoring interior lighting has lost communication or is sending invalid data about bulb failures.
Common Causes
40%
Body control module failure or corrupted memory
25%
Faulty overhead console module with lamp monitoring circuits
20%
Corroded connectors at interior lighting control modules
15%
Failed interior lamp bulb socket causing detection circuit fault
Diagnostic Steps
1
Step 1: Check all interior lights for proper operation (dome, map, courtesy, cargo lights)
2
Step 2: Inspect interior light sockets for corrosion, melted terminals, or water damage
3
Step 3: Monitor BCM data stream for interior lamp status parameters
4
Step 4: Check SCP network communication specifically between BCM and overhead console module
5
Step 5: Test door jamb switches and circuits that trigger interior lighting
Estimated Repair Cost
$80 - $400
Parts + labor, varies by vehicle and location
Communication fault on SCP J1850 network regarding interior lamp outage detection data. A module responsible for monitoring interior lighting has lost communication or is sending invalid data about bulb failures.
The most common cause of U1220 (SCP (J1850) Invalid or Missing Data for Interior Lamp Outage) is: Body control module failure or corrupted memory
Typical repair costs for U1220 range from $80 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Minimal safety impact as interior lighting malfunctions do not affect vehicle operation or visibility to other drivers. Primarily a convenience issue.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1220 to identify the root cause.
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Quick Info
Category
Network
System
Vehicle Communication Network / Interior Lighting System
Difficulty
Type
Manufacturer
Recommended Tools
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