P0B82

What it means

P0B82 means the hybrid or EV control unit has found that the signal from one of the traction battery voltage sense circuits, designated 'O', is out of range or does not match what it expects. The signal may disagree with other sense circuits, the pack total, or the expected behaviour under load. Which cell block or module the letter 'O' refers to depends on the manufacturer and model, so check the vehicle-specific documentation.

Symptoms

• Hybrid or EV system warning light, or malfunction indicator lamp, on
• Reduced power or limp-home mode
• Hybrid battery state of charge reading erratically or dropping quickly
• Engine running more often than normal on a hybrid, or reduced electric-only driving
• Reduced charging rate or charging refused on a plug-in or EV
• Car refusing to enter ready mode in some cases

Possible causes

• Poor connection or corrosion in the voltage sense wiring harness or connector at the battery pack or battery monitoring unitlikely
• Damaged, chafed or open-circuit sense wire between the cell block and the battery monitoring unitpossible
• Weak or imbalanced cell block or module causing a real voltage deviationlikely
• Faulty battery monitoring unit or voltage sensing circuit boardpossible
• Loose or corroded high-voltage busbar or terminal affecting the measured voltagepossible
• Water ingress or contamination inside the battery packrare
• Outdated control unit software where the manufacturer has issued a revision for this faultrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting battery state of charge, temperature and load when the code set, and look for other battery voltage or imbalance codes
2. Check for any manufacturer service bulletins or software updates for this code on the specific model
3. Carry out a visual inspection of the battery pack surround, cooling ducts and any accessible connectors for damage, moisture or corrosion, only if you are trained and the high-voltage system is isolated
4. Using live data, compare individual cell block or module voltages and look for one that deviates from the rest at rest and under load
5. Following the manufacturer's high-voltage safety procedure, isolate the system and check the sense circuit wiring and connectors for continuity, resistance and shorts to other circuits
6. Check busbar and terminal tightness and condition at the affected cell block
7. Check the battery monitoring unit's supply, ground and communication, and compare its readings with a verified reference measurement
8. Clear the code and road test, then recheck live data to confirm whether the fault returns

How to fix

• Repair or replace damaged sense wiring and clean or replace corroded connectors
• Rebalance or replace the weak cell block or module as the manufacturer's procedure specifies
• Tighten or replace faulty busbars and terminals to the specified torque
• Replace the battery monitoring unit if testing shows it is misreading
• Dry out and repair the pack and replace any affected parts if water has got in
• Update the control unit software if the manufacturer lists it as a fix for this fault

Can I keep driving?

Nearby codes

• P0B81GenericHybrid/EV Battery Voltage Sense O Circuit
• P0B83GenericHybrid/EV Battery Voltage Sense O Circuit Low