U0252 Lost communication with rear lighting control module B
What U0252 means
Rear lights on modern cars are often switched by a dedicated lighting module that receives commands over the vehicle network. U0252 means other modules stopped hearing from the second rear lighting module. Brake lights, tail lights, indicators or reversing lights it controls may not work.
U0252 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- High
- Typical repair cost
- 80–800 €
- Workshop time
- 0.5–3 h
- Repair difficulty
- Medium
- DIY possible
- No
- Check engine light
- No
- Affects emissions test
- No
- Limp mode possible
- No
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Bulb or lighting warning on the dashboard
- Rear lights, brake lights or indicators not working
- Lights working intermittently
- Trailer lighting faults
Common causes
- Blown fuse or failed power supply to the module
- Damaged wiring, often where the harness runs into the tailgate or boot lid
- Water ingress and corrosion in the module or its connector
- Poor ground at the module
- Failed lighting control module
Can I keep driving with U0252?
Get it checked today or tomorrow. If brake lights or indicators do not work, the car is a hazard to traffic behind you and will fail a technical inspection.
What to check first
- Walk around the car and check which rear lights, brake lights and indicators do not work
- Check the fuses supplying the rear lighting module
- Inspect the harness between body and tailgate or boot lid for broken wires, and the module connector for water
- Check power, ground and network wires at the module before replacing it
Related codes
- U0184 Lost communication with radio
- U0140 Lost communication with body control module
- U0127 Lost communication with tyre pressure monitor module
- U0126 Lost communication with steering angle sensor module
- U0121 Lost communication with ABS control module
- U0120 Lost communication with starter/generator control module
- U0109 Lost communication with fuel pump control module
- U0401 Invalid data received from engine control module (ECM/PCM A)
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
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