P0B55: Block-six rationality has a source-label discrepancy in its validity condition

P0B55 is the block-six voltage rationality code in this GM document. The printed failure equation compares both block six and block seven, each multiplied by twenty, with dedicated pack voltage. Both absolute differences must exceed 70V.

The paired equation is clear, but one enable label is not

The row requires run mode, suitable low-voltage supply and more than 200ms since contactor closure. It excludes the listed block-six circuit faults, pack-voltage faults and controller-performance fault. Its decision uses 160 failing samples out of 170 at 100ms intervals.

However, the validity line names block one rather than block six. The page does not establish whether that is intentional dependency or a copied label. This article does not silently replace the printed channel name or claim a fully resolved enable sequence.

Preserve the evidence needed to resolve applicability

Record block six, block seven, dedicated pack voltage, validity flags and controller calibration. The 70V value belongs to scaled block-to-pack differences, not a direct allowable voltage gap between neighboring blocks.

The source does not identify a shared wire fault or prove either physical block needs replacement. A trained high-voltage technician must consult the matching battery service information to resolve the validity condition and choose the correct diagnostic path. Pack access requires approved isolation and verification before physical testing.

That uncertainty affects enable attribution, rather than changing the printed failure equation.

Source and applicability

GM 2010 10OBDG10 Hybrid Diagnostics, only the cited controller and monitor. These are historical calibration examples; individual vehicle, engine and hardware applicability is not established. GM PDF, page 225.