U0183
Lost Communication With Lighting Control Module (Rear)
- Severity
- High
- Driving
- Short journeys only
The control module has stopped receiving messages from the rear lighting control module. On vehicles where lighting is switched by a module rather than directly by the stalk, this can mean lights that do not come on, do not go off, or do not dip. The consequences depend entirely on which lights are affected, and the ones that matter most are the ones you cannot see from the driver's seat.
Possible causes
- CommonLow battery voltage or a discharged battery, dropping modules off the bus
- CommonBlown fuse or corroded earth on the supply to the rear lighting control module
- CommonWater ingress at a lighting module or its connector
- CommonDamaged, chafed or corroded bus wiring
- PossibleFailed module
- PossibleAftermarket lighting or tow bar wiring spliced into the circuit
What you might notice
- Headlamps, tail lamps or indicators not working
- Lights staying on or not switching automatically
- Headlamp levelling stuck, dazzling oncoming drivers
- Bulb failure warnings for bulbs that are fine
- Brake lights or rear lamps inoperative
What to check, in order
- Have someone stand behind the car and confirm the brake lights, tail lamps and indicators all work before driving. No brake lights is how you get rear-ended, and it is the one symptom of this fault the driver cannot detect alone.
- Avoid driving at night until you have confirmed the headlamps work and dip correctly.
- Check battery voltage and state of charge before anything else. A weak or failing battery drops modules off the bus and sets lost-communication codes with no wiring fault at all - this is the single most common false lead in this whole family.
- Check the fuses and earths for the rear lighting control module. Rear lighting earths corrode particularly badly - they sit in the wettest part of the car.
- Look for water in the lamp units and their connectors.
- Ask whether tow bar wiring or aftermarket lighting has been fitted. Badly spliced tow bar wiring is a classic cause of rear lighting faults.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
U00xxU01xxU02xxU03xxU04xxU05xxU06xxU07xxU08xxU09xxU0AxxU0BxxU0CxxU0DxxU0ExxU0FxxU10xxU11xxU12xxU13xxU14xxU15xxU16xxU17xxU18xxU19xxU1AxxU1BxxU1CxxU1DxxU1ExxU1FxxU20xxU21xxU22xxU23xxU24xxU25xxU26xxU27xxU28xxU29xxU2AxxU2BxxU2CxxU2DxxU2ExxU2FxxU30xxU31xxU32xxU33xxU34xxU35xxU36xxU37xxU38xxU39xxU3AxxU3BxxU3CxxU3DxxU3ExxU3Fxx
Network communication
U0100U0101U0102U0103U0104U0105U0106U0107U0108U0109U0110U0111U0112U0113U0114U0115U0116U0117U0118U0119U0120U0121U0122U0123U0124U0125U0126U0127U0128U0129U0130U0131U0132U0133U0134U0135U0136U0137U0138U0139U0140U0141U0142U0143U0144U0145U0146U0147U0148U0149U0150U0151U0152U0153U0154U0155U0156U0157U0158U0159U0160U0161U0162U0163U0164U0165U0166U0167U0168U0169U0170U0171U0172U0173U0174U0175U0176U0177U0178U0179U0180U0181U0182U0183U0184U0185U0186U0187U0188U0189U0190U0191U0192U0193U0194U0195U0196U0197U0198U0199