Lost Communication With Lighting Control Module - Rear A
What it means
U0183 means the vehicle has lost communication with the rear "A" lighting control module — the computer that operates rear exterior lights such as tail, brake, turn, and reverse lamps. When it goes offline, some or all rear lighting can stop working or behave erratically. The car still drives, but missing brake lights or turn signals are a real safety and legal hazard. The cause is normally a wiring, connector, power/ground, or bus fault, often from rear moisture.
Can I keep driving? Driveable, but rear lighting (tail, brake, or turn signals) may not work — a safety and legal problem, especially at night. Get it fixed before driving after dark.
Common symptoms
What you'll notice
- Rear lights (tail, brake, turn, or reverse) not working or erratic
- Bulb-out or lighting warning messages
- Warning lights on
- Scan tool can't reach the rear lighting control module
Common causes
Most likely first
- Power or ground fault to the moduleLikely
- Damaged or corroded wiring/connector at the rear, where moisture collectsCommon
- Failed rear lighting control moduleCommon
- CAN bus wiring fault to the moduleLess often
How to diagnose & fix
Work through it in order
- Confirm which rear lights are affected and scan for related codes.
- Check the module's power and ground.
- Inspect rear wiring and connectors for corrosion or water damage.
- Verify bus communication to the module.
- Replace and program the module if it's confirmed faulty.
FAQ
Quick answers
Is it safe to drive with U0183?+
Can I just clear U0183?+
Related codes
Often seen with U0183
Read & clear U0183 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.