P0BB1: Sense X high is a timed upper-limit report

P0BB1 is the X-channel high-voltage measurement code in this GM 2015 battery controller. The reported cell voltage must reach at least 4.8 volts. The diagnostic is an upper-limit observation, not a direct determination of why the value is high.

Keep the duration with the voltage

The table requires 1.4 seconds of failure within a two-second window. This matters when an event is intermittent: a normal reading after the event does not explain the earlier qualified result. Equally, one isolated high sample does not establish the entire recorded condition.

Evaluation requires enabled operating-state communication. The listed open-sense-line faults, sensing-module communication faults, balancing faults and internal-performance faults must be absent; the secondary protection self-test must not be running.

Decide whether a retest is meaningful

If those prerequisites are blocked, the controller may not provide a fresh high-voltage assessment. Preserve the original fault context before interpreting a cleared warning or a non-returning code as verification. The source does not guarantee that all abnormal pack conditions will produce P0BB1.

The X channel must be matched to the exact battery and controller documentation. No physical connector location or battery-replacement instruction is established by this table. A trained high-voltage technician should verify the measurement and its supporting conditions before attributing the high report to the battery itself or its sensing electronics.

Source and applicability

15OBDG01 Hybrid Diagnostics, cited controller and monitor only. Historical calibration limits are not universal specifications; per-code vehicle, engine and hardware applicability must be verified.

GM source, physical page 631 · GM source, physical page 632.