OBD-II Code
P0B0F
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$800–$15,000+
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$800 (single module on Volt) to $15,000+ (full Bolt EV pack, recall-covered when applicable).
P0B0F means the BMS detected an out-of-range or implausible reading from the voltage sensor monitoring hybrid battery pack 2 — applies to platforms with multiple physical pack modules (typical of plug-in hybrids and longer-range EVs where the pack is split into 2+ module strings).
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0B0F means the BMS detected an out-of-range or implausible reading from the voltage sensor monitoring hybrid battery pack 2 — applies to platforms w…
P0B0F means the BMS detected an out-of-range or implausible reading from the voltage sensor monitoring hybrid battery pack 2 — applies to platforms with multiple physical pack modules (typical of plug-in hybrids and longer-range EVs where the pack is split into 2+ module strings). The code can fire from a hard sensor failure, a wiring fault, or a real cell-block voltage divergence within pack 2 that the BMS cannot reconcile against pack 1.
Shop-floor ladder
- Pull live data for individual cell-group voltages in both packs — healthy Li-ion cells sit at 3.6-4.2V depending on state-of-charge, with intra-pack delta under 50mV at rest; any single group sagging 100mV+ below its peers is a weak cell-block.
- If all groups in pack 2 read normal but the pack-level sensor disagrees with the sum-of-groups, the voltage sensor itself is bad — sensor swap at the pack BMS slave board.
- Wiring check: backprobe the pack-2 voltage-sense harness at the master BMS connector (NOT the HV bus — this is a low-voltage sense circuit) for continuity and shield integrity.
- Pack-balance test if your scan tool supports it — multi-pack platforms can sometimes recover from a divergence event with a guided rebalance cycle.
- If a cell-block in pack 2 is genuinely failed, single-module replacement is often possible on modular platforms (Volt, Leaf) for significantly less than a full pack swap. DO NOT probe HV orange-wire circuits with a standard multimeter. Always service HV with Class 0 1000V gloves, isolation tester (Megger), and DC-rated lugged probes. Pack contactor stuck-closed (P0AF1/P0AF2) is the only condition where the orange-wire bus may be live AFTER the service plug is removed. NEVER assume zero potential — always measure with an HV-rated meter.
Vehicle-specific patterns2012-2015 Toyota Prius Plug-in (PHV) uses a split Li-ion pack and is a common P0B0F platform — the pack-2 voltage sensor on the BMS slave board fails…
- 2012-2015Toyota Prius Plug-in (PHV) uses a split Li-ion pack and is a common P0B0F platform — the pack-2 voltage sensor on the BMS slave board fails around 80-120k miles, often without any cell-level fault, and a slave-board swap at a hybrid specialist clears it.
- 2011-2015Chevy Volt Gen1 and 2016-2019 Volt Gen2 use a T-shaped pack with multiple module strings; P0B0F here typically traces to a single weak module group and GM's modular pack design allows single-module replacement at ~$800-$1,200.
- 2013-2017Ford C-Max Energi and Fusion Energi follow the Volt module pattern.
- 2017-2022Chevy Bolt EV (LG Chem pack) throws P0B0F-family codes from the well-documented LG cell defect that prompted the 2020-2021 recall — confirm VIN coverage before quoting work, GM may cover pack replacement under recall.
- 2013-2019Nissan Leaf Gen2 (40kWh and 62kWh packs) throws this from heat-stressed module groups in hot-climate fleet vehicles.
Estimated repair$800 (single module on Volt) to $15,000+ (full Bolt EV pack, recall-covered when applicable).
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