What are the common causes of P0BB4?

A Y circuit voltage reading outside the expected window. A drifting Y voltage tap. A high resistance joint in the Y sense lead. A weak cell at the Y tap. A calibration fault in the Y sense channel.

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

P0BB4

Hybrid/EV Battery Voltage Sense Y Circuit Range/Performance

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

What it means

P0BB4 means Hybrid/EV Battery Voltage Sense Y Circuit Range/Performance.

Check these first

A Y circuit voltage reading outside the expected window
A drifting Y voltage tap
A high resistance joint in the Y sense lead
A weak cell at the Y tap
A calibration fault in the Y sense channel

What to do next

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

Look up another code

Code or symptom

Enter a full code or a symptom. Press / to search. How to read a code

Type a code above, or start from a symptom or a common code.

Updated

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