P0B96

What it means

P0B96 means the hybrid or EV battery control unit saw the signal from one of its battery voltage sense circuits (circuit 'S') fall outside the expected range, or disagree with other voltage readings. The reading did not make sense compared with the other sense circuits, the total pack voltage or the expected behaviour under load. Which cell group or module circuit 'S' refers to depends on the vehicle and battery design, so check the manufacturer data for the exact model.

Symptoms

• Hybrid or EV system warning light on, often with the main warning light
• Reduced power or limp mode
• Poor or erratic state-of-charge reading
• Reduced electric-only range or the engine running more than usual
• Car refuses to enter ready mode or the high voltage system shuts down
• Charging slower than normal or stopping early

Possible causes

• Faulty or loose connector, terminal or wiring in the voltage sense harness between the battery modules and the battery control unitlikely
• Imbalanced or degraded cells or modules in the high voltage battery giving a genuinely abnormal voltagelikely
• Faulty battery monitoring unit or cell sensing boardpossible
• Corrosion, moisture ingress or contamination in the battery pack or its connectorspossible
• Loose or corroded high voltage busbar or module connection causing voltage drop or erratic readingspossible
• Outdated or faulty control unit software where the manufacturer has issued a correctionrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting any other battery voltage, temperature or insulation codes, as related codes help narrow down the cause.
2. Check for manufacturer bulletins or known software updates for this model and battery type.
3. Only a technician trained in high voltage systems should go further. Follow the manufacturer's safe isolation procedure before touching any battery or high voltage components.
4. Inspect the battery sense harness and connectors for damage, corrosion, moisture, bent or pushed-back pins and poor locking.
5. Using live data, compare individual cell or module voltages and the total pack voltage, and look for one reading that is out of line or jumping about.
6. Check the voltage sense circuit for continuity, resistance and short circuits against the manufacturer's wiring data for circuit 'S' on this vehicle.
7. Check busbar and module connections for tightness and signs of heating or corrosion, following the manufacturer's torque and procedure data.
8. Perform the manufacturer's battery balance or capacity test to see whether a cell group is weak.

How to fix

• Repair or replace damaged wiring, terminals or connectors in the sense circuit.
• Clean and dry out contaminated connectors, and correct the cause of any moisture ingress.
• Rebalance the battery, or repair or replace the faulty module or cell group, as the manufacturer's procedure directs.
• Replace the faulty battery monitoring unit or sensing board if testing confirms it.
• Retighten or replace affected busbar connections to the specified torque.
• Apply a manufacturer software update if one is available for this fault.

Can I keep driving?

Nearby codes

• P0B95GenericHybrid/EV Battery Voltage Sense S Circuit
• P0B97GenericHybrid/EV Battery Voltage Sense S Circuit Low