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DTC codes / P0Bxx · Hybrid propulsion / P0B16

P0B16Hybrid/EV Battery Pack Voltage Sense B Circuit Low

P0B16 indicates that the hybrid or electric vehicle battery pack voltage sensing circuit B is reporting a voltage lower than the expected range, as detected by the battery energy control module. The computer compares the signal from this specific sense circuit against other voltage sense circuits and flags a fault when the reading is implausibly low, which can affect the accuracy of state-of-charge and power limit calculations.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyProfessional
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the hybrid system warning light or service vehicle soon message
  • Reduced electric-only range or the vehicle refusing to enter EV mode
  • A sudden drop in available power or limp-home mode under load
  • Inaccurate or fluctuating state-of-charge display on the dashboard
  • Often no symptoms besides the warning light, especially if the fault is intermittent

Common causes, most likely first

  1. Damaged or chafed wiring in the voltage sense circuit B harness, particularly near the battery pack connectors
  2. Corroded or loose terminals at the battery pack voltage sense connector
  3. Internal failure of the battery pack voltage sense module or the sense line within the pack
  4. Faulty cell voltage sensor or sensing harness inside the high-voltage battery assembly
  5. Water intrusion or contamination in the battery pack connector causing a low-resistance path
  6. Battery energy control module software glitch or internal fault causing a false low reading

How to diagnose and fix it

  1. Inspect the voltage sense circuit B wiring and connectors for damage, corrosion, or loose pins, and repair as needed
  2. Measure the sense circuit voltage at the battery pack connector and compare it with the module-reported value to confirm the discrepancy
  3. Perform a voltage drop test on the sense circuit while wiggling the harness to expose intermittent faults
  4. Check for water intrusion or contamination in the battery pack area and dry or clean the connectors
  5. Substitute a known-good voltage sense module or sensor if the wiring and connectors test good
  6. Reprogram or update the battery energy control module software if a known calibration issue exists
  7. Replace the faulty cell voltage sensor or sense harness inside the battery pack if internal faults are confirmed

What the sense circuit B code hides

  • A low voltage reading on one sense circuit often results from a poor connection rather than a failing battery pack, so always perform a voltage drop test before condemning expensive components.
  • Intermittent P0B16 codes frequently appear after battery pack service or connector reseating, and the fault may clear after simply cleaning and reseating the connector.
  • The battery energy control module may set this code even when the actual cell voltages are normal, because it compares sense circuit B against other sense circuits and flags any implausible difference.
  • Water intrusion into the battery pack connector is a commonly missed cause, especially on vehicles that have been driven through deep water or in regions with heavy road salt use.
  • A weak 12-volt auxiliary battery can cause erratic module behavior and false sense circuit codes, so always verify the low-voltage system is healthy before deep diagnostics.

Can I keep driving with P0B16?

You can usually drive the vehicle, but avoid aggressive acceleration or sustained high-speed driving because the reduced accuracy of the battery monitoring may cause the system to limit power unexpectedly. Have the fault diagnosed soon to prevent potential stranded situations or further battery pack damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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