Code
P0ED2
Generic
P — Powertrain
Hybrid/EV Battery F Voltage Low
Views:
UK: 16
EN: 24
RU: 13
AI status
Completed
Completed
100%
Causes
- One or more weak/failed cells inside battery subpack/module F
- Poor or corroded wiring/connector to module F or its sense leads
- Faulty module voltage sensor or BMS sense circuit for module F
- Open or high-resistance contactor/fuse in HV supply path to module F
- Severe state-of-charge (SOC) imbalance or depleted module
- High internal resistance due to age, overheating, or damage
Symptoms
- Reduced propulsion power or limp-home / reduced EV drive
- Hybrid/EV warning light or battery warning message on dash
- Reduced regenerative braking or altered charging behavior
- Incorrect or inconsistent pack/module voltage readings on scan tool
- Vehicle may refuse to enter EV mode or will shut down high-voltage output
What to check
- Read stored/active freeze-frame data and full DTC list with a capable OBD2/BMS scanner
- Verify overall high-voltage battery pack voltage against specifications
- Check individual module F voltage and compare to other modules
- Inspect HV connectors, sense leads, and harness to module F for corrosion, damage, or looseness
- Check HV fuses, contactors/relays and their control circuits
- Review BMS and charger communication messages (CAN/BMS diagnostics)
Signal parameters
- Battery pack (total) voltage — expected range per vehicle model
- Module F voltage — expected per-module nominal voltage and threshold
- Individual cell voltages within module F (min, max, and average)
- State of charge (SOC) at time of fault
- Battery current (charge/discharge) during fault
- Module F temperature
Diagnostic algorithm
- Safety first: follow manufacturer HV safety procedures — disable high-voltage system, remove service plug, and use PPE before accessing components.
- Connect a factory-level or OEM-capable scanner and record DTCs, freeze-frame and live-data for pack voltage, module F voltage, cell voltages, SOC, current and temperatures.
- Visually inspect the HV harness, connector pins and module F sense leads for damage, corrosion, or poor seating; repair or reseat as needed.
- With HV system safely isolated and per service manual, measure module F terminal/sense voltages directly and compare to scanner values to confirm sensor/BMS accuracy.
- Check continuity and resistance of sense wiring and communication lines between module F and the BMS; repair high-resistance/open circuits.
- Inspect and test HV contactors/fuses/relays and their control circuits to confirm module F can be connected and charged. Replace faulty components.
- If module F voltage is low under load, perform controlled charge/discharge tests per vehicle procedure to determine if voltage recovers. Monitor individual cell behavior for imbalance or failed cell(s).
- If a specific failed cell or internal module fault is identified, follow OEM guidance for module replacement or cell repair. Do not attempt cell-level repair unless qualified and following manufacturer procedures.
- After repair, clear DTCs, perform any required BMS relearn or balancing routines, charge the pack fully per procedure, then verify fault does not return under normal operation.
- If diagnostics are inconclusive, return the vehicle to dealer or specialized HV battery repair facility for advanced module evaluation and possible replacement.
Likely causes
- Failed cell(s) within module F causing low module voltage
- Loose or damaged sense lead or connector to module F
- Faulty BMS voltage sensing hardware for that module
- HV isolation fault or open fuse/contactor preventing module charging
- Module temperature extreme causing temporary voltage sag
Fault status
Status
Hybrid/EV Battery F Voltage Low — battery subpack/module F measured below expected voltage threshold. May limit drive performance or disable EV drive.
Repair difficulty: Hard
Diagnostic time: 2-6 hours
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