Damaged, corroded, or disconnected wiring or connector at the rear lighting control module; Open or short circuit in the controller area network (CAN) bus wiring between the rear lighting module and the network gateway; Failed rear lighting control module due to water intrusion, internal component failure, or power supply issue; Blown fuse or faulty relay supplying power to the rear lighting control module; Poor ground connection at the rear lighting module mounting point or chassis ground; Software glitch or corrupted configuration in the rear lighting control module requiring reprogramming; Faulty network gateway module that is not properly relaying messages to the rear lighting module

DTC codes / U01xx · Lost communication with a control module / U0183

U0183Lost Communication With Lighting Control Module Rear

Q: What does code U0183 mean?

Lost Communication With Lighting Control Module Rear. U0183 is a generic network communication fault indicating that the module responsible for monitoring the vehicle's data bus has lost contact with the rear lighting control module. The computer sets this code when it expects regular status messages from the rear lighting module but receives no response or an invalid signal over the communication network.

U0183 is a generic network communication fault indicating that the module responsible for monitoring the vehicle's data bus has lost contact with the rear lighting control module. The computer sets this code when it expects regular status messages from the rear lighting module but receives no response or an invalid signal over the communication network.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaLost communication with a control module

Symptoms you may notice

Illumination of the check engine light or a dedicated communication fault warning on the dashboard
Rear tail lamps, brake lamps, turn signals, or reverse lamps may fail to operate or behave erratically
The rear lighting module may default to a failsafe mode, causing lamps to stay on continuously or not light at all
Other unrelated electrical accessories may act intermittently if the network bus is compromised
Often no symptoms besides the warning light, especially if the fault is intermittent and the module reconnects

Common causes, most likely first

Damaged, corroded, or disconnected wiring or connector at the rear lighting control module
Open or short circuit in the controller area network (CAN) bus wiring between the rear lighting module and the network gateway
Failed rear lighting control module due to water intrusion, internal component failure, or power supply issue
Blown fuse or faulty relay supplying power to the rear lighting control module
Poor ground connection at the rear lighting module mounting point or chassis ground
Software glitch or corrupted configuration in the rear lighting control module requiring reprogramming
Faulty network gateway module that is not properly relaying messages to the rear lighting module

How to diagnose and fix it

Inspect the rear lighting control module connectors for corrosion, loose pins, or water damage and clean or repair as needed
Check all fuses and relays related to the rear lighting control module and replace any that are blown or faulty
Test the CAN bus wiring for continuity, shorts to ground, or shorts to power using a digital multimeter and wiring diagram
Verify the rear lighting control module has proper power and ground at its connector with the key on
Perform a voltage drop test on the ground circuit to confirm a solid ground connection
If wiring and power are good, substitute a known-good rear lighting control module or reprogram the existing module with the latest software
Clear the code and perform a road test to confirm communication is restored and the code does not return

Network faults often mimic lighting failures

A rear lighting control module that has lost communication may still illuminate bulbs in a default mode, leading technicians to replace good bulbs instead of addressing the network fault.
Water intrusion into the rear lighting module connector is a common cause that is frequently overlooked because the module is often located behind interior trim panels where leaks go unnoticed.
The U0183 code can be set by a low battery or charging system issue that causes momentary voltage drops, so always check battery health and charging voltage before condemning the module.
Aftermarket LED bulbs or trailer wiring modifications can introduce electrical noise on the lighting circuit that disrupts communication, even though the module itself is healthy.
Some vehicles require a relearn or initialization procedure after replacing the rear lighting control module; skipping this step will leave the U0183 code stored even with a new module.

Can I keep driving with U0183?

If the only symptom is a warning light and all rear lamps function normally, the vehicle is generally safe to drive to a repair shop, but avoid towing a trailer or relying on rear lighting in low-visibility conditions. If rear lamps are inoperative or stuck on, do not drive at night or in poor weather until the fault is repaired, as this creates a safety hazard.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.