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DTC codes / P0Bxx · Hybrid propulsion / P0B87

P0B87Hybrid/EV Battery Voltage Sense P Circuit Range/Performance

P0B87 indicates that the hybrid or electric vehicle battery pack controller has detected an out-of-range or performance fault in the voltage sensing circuit for battery module group 'P'. The computer compares the voltage reported by this sense circuit against expected values from other modules and flags the code when the signal is implausible, erratic, or outside the allowable range.

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
  • Often no symptoms besides the warning light, especially if the fault is intermittent
  • Reduced electric-only range or the vehicle refusing to enter EV mode
  • Powertrain power limitation or limp-home mode in severe cases
  • Inconsistent state-of-charge readings on the dashboard display
  • Possible failure to start or charge if the battery management system disables the pack

Common causes, most likely first

  1. Faulty voltage sense wire or connector at the battery module group P (corrosion, chafing, or loose terminal)
  2. Open or high-resistance sense fuse or inline resistor in the voltage sensing circuit
  3. Failed battery module group P causing abnormal voltage behavior under load
  4. Defective battery management system (BMS) controller or voltage sensing integrated circuit
  5. Software calibration error in the BMS requiring reprogramming
  6. Water intrusion or contamination in the battery pack connector or sense harness
  7. Loose or degraded battery pack ground connection affecting voltage reference

How to diagnose and fix it

  1. Inspect the voltage sense harness and connector at battery module group P for corrosion, damage, or loose pins
  2. Measure resistance and voltage drop across the sense circuit from the module to the BMS controller
  3. Check the sense fuse and any inline resistors for continuity and correct resistance
  4. Compare live voltage readings from all module groups using a scan tool to isolate the faulty group
  5. Perform a battery pack load test and capacity check to rule out a failing module group P
  6. Reprogram or update the BMS software if a known calibration issue exists
  7. Replace the faulty sense harness, module group, or BMS controller as confirmed by testing

Sense circuit faults often mimic module failure

  • A loose or corroded sense connector at module group P is far more common than an actual battery module failure, so always inspect the harness before condemning the pack.
  • Intermittent P0B87 codes that appear only under vibration or temperature extremes often trace to a chafed wire rather than a defective BMS.
  • Some vehicles set this code after a low-voltage event or battery replacement if the BMS learns an incorrect reference, and a relearn procedure clears it without parts.
  • The code does not always mean the battery pack is degraded; a simple voltage divider resistor inside the BMS can fail and skew the reading.
  • Aftermarket chargers or improper jump-starting can spike the sense circuit and set P0B87 without any permanent damage.

Can I keep driving with P0B87?

You can usually drive the vehicle short distances to a service location, but avoid heavy acceleration, fast charging, and long trips until the fault is diagnosed. If the hybrid system warning is accompanied by power reduction or a refusal to start, stop driving and arrange a tow.

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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