Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer has detected a problem with one of the sensors that checks the battery's voltage. It's like if your game console said there was a problem with the battery pack, so it can't tell how much power is left.
The P0B91 code is triggered when the hybrid or electric vehicle's control module detects an issue with the voltage sensing circuit 'R' of the battery. This could mean the voltage is too high, too low, or fluctuating unexpectedly.
The P0B91 code indicates a range or performance issue with the Hybrid/EV battery voltage sense circuit 'R'. This circuit is responsible for monitoring the voltage of a specific section of the battery pack. If the voltage readings from this circuit fall outside the expected range, the vehicle's control module will set this code.
• Check Engine Light is on
• Reduced fuel efficiency
• Limited power or performance from the vehicle
• Faulty battery voltage sensor
• Damaged or corroded wiring or connectors
• Malfunctioning battery control module
OBD-II: On-Board Diagnostics, a standardized system for self-diagnostics and reporting in vehicles.
Battery Control Module: A component that manages the battery's performance and health.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the battery voltage sensor for proper operation.
• Replace the faulty battery voltage sensor.
• Repair or replace damaged wiring or connectors.
• Replace or reprogram the battery control module if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Toyota Prius
• Chevrolet Volt
• Nissan Leaf
• Regularly inspect battery connections and wiring.
• Ensure the battery is maintained according to manufacturer recommendations.
• Avoid exposing the vehicle to extreme temperatures.
Sensor Issue
• Do not ignore the Check Engine Light; have the vehicle inspected promptly.
• Avoid driving the vehicle aggressively until the issue is resolved.
Battery and related components may be covered under the vehicle's hybrid system warranty.
This code has been more common in older hybrid models as battery systems age and sensors become less reliable.
Moderate – While the vehicle may still operate, performance and efficiency could be affected.
Driving with a malfunctioning battery sensor can lead to reduced performance and efficiency, potentially affecting vehicle safety.
• Vehicle must be in a safe, stationary position.
• Ensure the battery is fully charged before testing.
The battery voltage sensor is typically located within the battery pack or near the battery control module.
Q: Can I drive my car with a P0B91 code?
A: It's possible to drive, but it's not recommended as it may affect performance and efficiency.
Q: How do I reset the P0B91 code?
A: After repairs, use an OBD-II scanner to clear the code, but ensure the issue is fixed to prevent recurrence.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
View on Amazon
Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.