What does it mean?
B1252 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Combination Switch Control Unit Internal (EEPROM) Error .
Symptoms
- A warning lamp appears in the instrument cluster and stalk functions behave unpredictably
- Wipers, turn signals, headlamps, or the horn work intermittently or not at all
- Intermittent wipe and automatic light features stop working
- The fault usually returns immediately after it is cleared
- Other modules may report lost communication with the switch unit
Likely causes
- Internal memory failure inside the combination switch control unit
- Low or unstable supply voltage during cranking or a jump start, corrupting stored data
- Power interrupted or the battery disconnected during a module write or programming procedure
- Corroded or loose power and ground connections at the control unit
- Moisture reaching the unit at the steering column, often from a windshield or cowl leak
- Voltage spike from a charging system fault or from welding carried out on the vehicle
How to fix it
- Check battery condition and charging system output first, since memory errors often follow low voltage events
- Inspect and clean the power and ground connections at the combination switch control unit
- Check the connector at the steering column for moisture, corrosion, and loose terminals
- Try clearing the code with a fully charged battery; if it returns straight away the internal memory is damaged
- Confirm the unit has the correct software and configuration if it has recently been replaced
- Replace the combination switch control unit and carry out the configuration procedure required for the vehicle