U0183: Lost Communication with Rear Lighting Module
Diagnostic trouble code U0183 indicates a loss of communication between the powertrain control module (PCM) or body control module (BCM) and the rear lighting control module. This means the main control module is not receiving or sending data over the communication bus (typically CAN, LIN, or SCP) to the module responsible for managing the vehicle's rear lights. According to SAE J2012, 'U' codes are network communication faults. When this code sets, it usually means the expected voltage or data signal from the rear module has timed out or the bus has a total failure.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Damaged or unpowered rear lighting control module (LCM Rear)
- Open circuit or short to ground in the communication bus wiring (CAN/LIN)
- Blown fuse or defective relay supplying power to the rear lighting module
- Corroded, bent, or pushed-back pins in the electrical connectors at the rear module
- Faulty body control module (BCM) or network gateway
- Poor ground connection in the rear area of the vehicle
3. Symptoms You Will Notice
- Rear lights (tail, brake, turn signals, reverse) may be inoperative or malfunctioning
- Check Engine Light or other warning lights illuminated on the dashboard
4. Step-by-Step Diagnosis
Scan for all stored codes and note any related communication or module codes
Check the fuse(s) and relay(s) for the rear lighting module and replace if blown
Inspect the wiring and connectors at the rear lighting module for damage, corrosion, or poor pin contact
Verify power and ground at the rear lighting module using a multimeter
Test the communication bus (CAN/LIN) for proper voltage and signal with an oscilloscope or scan tool
If all else is good, suspect a faulty rear lighting module and replace it
5. Frequently Asked Questions
Is it safe to drive?▼
Driving with U0183 is not recommended because rear lights may not work properly, creating a safety hazard and potential legal issues. Have the vehicle diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs vary widely depending on the root cause. A simple fuse replacement can cost under $20, while replacing a rear lighting module may range from $200 to $600 including parts and labor.