P0B83

What it means

P0B83 is the generic code for a low signal in the hybrid or EV battery voltage sense circuit designated 'O'. The battery control unit saw the voltage reported by that sense circuit fall below the expected range, or read it as implausibly low compared with the other sense circuits or the total pack voltage. Which cell block, module or sensor 'O' refers to depends on the manufacturer and model, so check the vehicle-specific data.

Symptoms

• Hybrid or EV system warning light on, often with the main malfunction light
• Reduced power or limp-home mode
• Hybrid assist or EV driving range limited or unavailable
• Poor or erratic state-of-charge reading
• Engine running more than usual on a hybrid
• Car refuses to enter ready mode in some cases

Possible causes

• Damaged, loose, corroded or contaminated connector or wiring on the battery voltage sense circuitlikely
• Open circuit or high resistance in a sense lead, or a blown or failed sense line fuse where fittedpossible
• Genuinely low cell block or module voltage from an imbalanced or degraded battery packlikely
• Fault in the battery monitoring unit or its internal voltage sensing circuitpossible
• Short to earth in the sense wiring after damage, water ingress or previous repair workpossible
• Poor busbar or terminal connection inside the packrare
• Outdated control unit software where the manufacturer has issued a fix for this faultrare

How to diagnose

1. Read all stored and pending codes with freeze frame data, noting battery state of charge, pack voltage, temperature and whether other battery voltage or imbalance codes are present.
2. Check for manufacturer service bulletins and software updates relevant to the model and fault.
3. Only a technician trained in high-voltage systems should go further. Follow the manufacturer's procedure to power down and isolate the high-voltage system, and wear the correct protective equipment.
4. Visually inspect the battery pack area, vents, connectors and sense harness for damage, corrosion, moisture, rodent damage or signs of previous repairs.
5. Use live data to compare the individual cell block or module voltages with the total pack voltage and identify which circuit 'O' refers to on this model.
6. With the system isolated, check the sense circuit wiring for continuity, resistance and short to earth against the wiring diagram, and check any related fuses.
7. Check for pack imbalance or a weak module by comparing voltages under load and at rest, following the manufacturer's test procedure.
8. If the wiring and pack are sound, test the battery monitoring unit's supply, earth and communication before condemning it.

How to fix

• Repair or replace damaged wiring, and clean or replace corroded or loose connectors in the sense circuit.
• Replace any failed fuse only after finding and fixing the cause.
• Rebalance or repair the battery pack, or replace the affected module or cell block, as the manufacturer's procedure allows.
• Replace the battery monitoring unit if it is confirmed faulty, and complete any required coding or setup.
• Update the control unit software if an applicable update is available for this fault.
• Clear the code after repair and road test to confirm it does not return.

Can I keep driving?

Nearby codes

• P0B82GenericHybrid/EV Battery Voltage Sense O Circuit Range/Performance
• P0B84GenericHybrid/EV Battery Voltage Sense O Circuit High