P2DB9Battery Charging System B High Voltage Interlock Circuit Low
- Generic OBD-II code · Powertrain
- How the car detects it
- P2DB9 is stored when the sensed voltage of the charging system B interlock loop stays too low. Since the module feeds a test voltage into the loop, a low reading usually means current is escaping to ground: a chafed wire touching the body, moisture in a connector, or a failing measuring stage inside the module. No manufacturer documents P2DB9 publicly. For the A-side loop of the Chevrolet Volt, GM's 2011 and 2014 tables call the reading faulty when it drops under 30 % of the sourced 5 V in two of two 12.5 ms samples, rated Type A (P0D17); that logic is a fair model for loop B. The high counterpart is P2DBA, a clean open P2DB7. Path B will not be used for charging until the fault is cleared.
- What you may notice
- Charging through path B not possible
- Charging system warning message
- Likely causes
- LikelyInterlock wire chafed through and touching ground
- PossibleWater or dirt in an interlock connector causing leakage to ground
- RareDefective interlock source or measuring stage in the control module
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.