What are the common causes of P0B91?

An R circuit voltage reading outside the expected window. A drifting R voltage tap. A high resistance joint in the R sense lead. A cell at R reading high or low. A calibration fault in the R sense channel.

Compare R circuit voltage to adjacent taps. Watch R voltage across a full drive cycle. Inspect the R sense lead for added resistance. Test the R cell tap under load. Replace the sense module if R stays out of range. Clear the code and retest.

P0B91

Hybrid/EV Battery Voltage Sense R Circuit Range/Performance

System: Powertrain control (P code)
Lamp: Check Engine Light
Category: Powertrain - Hybrid Propulsion

What it means

P0B91 means Hybrid/EV Battery Voltage Sense R Circuit Range/Performance.

Check these first

An R circuit voltage reading outside the expected window
A drifting R voltage tap
A high resistance joint in the R sense lead
A cell at R reading high or low
A calibration fault in the R sense channel

What to do next

Compare R circuit voltage to adjacent taps
Watch R voltage across a full drive cycle
Inspect the R sense lead for added resistance
Test the R cell tap under load
Replace the sense module if R stays out of range
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.