P0B6F

What it means

P0B6F means the hybrid or EV battery control unit saw the signal from voltage sense circuit 'K' of the high-voltage battery pack read lower than its expected range. This is a circuit fault, so it points to the sensing path (wiring, connector, sense lead or monitoring electronics) or a genuinely low voltage at that sense point. Which cell, module or pack section circuit 'K' covers depends on the vehicle, so check the manufacturer data for the model.

Symptoms

• Hybrid or EV system warning light, or malfunction indicator lamp, on
• Reduced power or limited electric assist or EV range
• Hybrid battery state-of-charge reading erratic or inaccurate
• Car refusing to enter ready mode or high-voltage charging being limited or interrupted
• Engine running more often than usual on a hybrid
• Other battery voltage sense or battery imbalance codes stored alongside it

Possible causes

• Loose, corroded or damaged connector or terminal on the battery voltage sense circuitlikely
• Open circuit, chafed or broken sense wire or harness in the sense lead to the battery monitorlikely
• Fault in the battery monitoring or battery control unit's sense inputpossible
• Genuinely low voltage in the cell group or module covered by circuit K (weak or failed cells, high internal resistance, imbalance)possible
• Moisture or contamination ingress in the battery pack or its connectorspossible
• Poor connection at a busbar or sense tap inside the packrare
• Outdated control unit software where the manufacturer has a known fix for the modelrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting battery state of charge, pack voltage, temperature and whether other sense circuit or imbalance codes are present.
2. Check for manufacturer service bulletins and software updates for this model and fault code.
3. Only a technician trained in high-voltage systems should go further: follow the manufacturer's procedure to isolate and verify the high-voltage system is safe before touching any battery wiring.
4. Visually inspect the battery pack sense harness and connectors for damage, corrosion, moisture, pin push-out or poor locking.
5. Look at live data for individual cell or module voltages and compare the group covered by circuit K with the others for an abnormal low reading or a reading stuck at zero.
6. Test the sense circuit for continuity, resistance to ground and short circuits against the wiring diagram, with the system isolated.
7. Clear the code, wiggle test the harness and road test, watching whether the fault returns and whether the reading drops out suddenly (suggests wiring) or tracks real voltage (suggests a weak cell group).
8. If wiring is good and the cells are healthy, check the monitoring unit's supply, ground and sense input before condemning it.

How to fix

• Clean, repair or replace faulty connectors and terminals on the sense circuit.
• Repair or replace the damaged sense wire or harness section.
• Dry out and rectify any moisture ingress, and fix the source of the leak.
• Rebalance, repair or replace the affected battery module or cell group if its voltage is genuinely low, following the manufacturer's procedure.
• Replace the battery monitoring or control unit if it is confirmed faulty, and carry out any required programming.
• Apply a manufacturer software update if the fault is a known calibration issue for the model.

Can I keep driving?

Nearby codes

• P0B6EGenericHybrid/EV Battery Voltage Sense K Circuit Range/Performance
• P0B70GenericHybrid/EV Battery Voltage Sense K Circuit High