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byd_12v01
Easy Fix
BYD · Electric & Hybrid Cars
12V Auxiliary Battery Low
Quick Answer
Error code BYD_12V01 on your BYD Electric & Hybrid Cars means: 12V Auxiliary Battery Low. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
BYD-A3BYD-DPBYD-HNBYD-SLBYD-SUBYD-SPBYD-TG
Likely Causes
  1. 12V auxiliary battery reaching end of service life with insufficient capacity to hold charge
  2. DC-DC converter malfunction failing to replenish 12V battery from the high-voltage pack
  3. Parasitic current draw from vehicle modules during sleep mode draining the 12V battery
  4. Corroded or loose 12V terminal connections creating excessive resistance
  5. Prolonged vehicle storage without any charging activity depleting the 12V system
How to Fix It
1
Measure 12V battery resting voltage with a multimeter; should be 12.4V or higher
2
Check charging voltage with the vehicle powered on; should be between 13.5V and 14.5V
3
Inspect both 12V battery terminals for corrosion and clean with a terminal cleaning brush
4
Connect the vehicle to AC charging to allow the DC-DC converter to charge the 12V battery
5
Replace the 12V auxiliary battery if it fails a load test or does not retain charge
Pro Tip
This is a common issue that most users can resolve without specialized tools. Try the first step before moving on to more complex solutions.
Parts You May Need
12V auxiliary battery (BYD-compatible specification)
DC-DC converter module if found defective
Battery terminal cleaning kit and dielectric grease
Multimeter for load and voltage testing
Related Error Codes
BYD_BMS01BYD_BMS02BYD_BMS03BYD_CHG01BYD_CHG02
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