What Does P0B87 Mean?
The battery management system has detected that the voltage reading from hybrid battery sense circuit "P" is outside the expected range or is not performing correctly relative to other cell groups. The signal is present but does not correlate with expected battery behavior, indicating possible cell imbalance or sensor drift within that module.
Common Causes
40%
Cell imbalance or degradation within battery module "P" causing voltage to deviate from expected range
25%
High resistance in the voltage sense circuit due to corroded terminal or splice
20%
Battery management controller calibration drift or software issue
15%
Temperature-related voltage variation due to failed cooling in the area of module "P"
Diagnostic Steps
1
Step 1: Monitor cell group "P" voltage in real time and compare to all other cell groups — note the deviation percentage; more than 0.3V difference under load is abnormal.
2
Step 2: Check battery temperature sensor readings near module "P" to ensure the module is within the normal thermal range (typically 20-40°C during operation).
3
Step 3: Perform a battery capacity/balance test using the manufacturer-specific battery diagnostic tool to evaluate individual cell health within the module.
4
Step 4: With the HV system de-energized, measure the actual cell/module voltage directly at the module terminals with a high-impedance DVOM and compare to the scan tool reading to rule out sense circuit resistance issues.
5
Step 5: Inspect the cooling air pathway near module "P" for blockages, collapsed ducts, or debris that could cause localized overheating.
Estimated Repair Cost
$200 - $4,000
Parts + labor, varies by vehicle and location
The battery management system has detected that the voltage reading from hybrid battery sense circuit "P" is outside the expected range or is not performing correctly relative to other cell groups. The signal is present but does not correlate with expected battery behavior, indicating possible cell ...
The most common cause of P0B87 (Hybrid Battery Voltage Sense "P" Circuit Range/Performance) is: Cell imbalance or degradation within battery module "P" causing voltage to deviate from expected range
Typical repair costs for P0B87 range from $200 to $4,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Reduced hybrid system performance is likely. Continued driving with a significantly imbalanced cell group can accelerate degradation of the entire battery pack. Schedule service soon.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0B87 to identify the root cause.
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Quick Info
Category
Powertrain
System
Hybrid Battery Pack / High-Voltage System
Difficulty
Type
Generic (SAE)
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