P0B69: block 10 rationality compares two scaled readings with the pack

P0B69 is a plausibility diagnosis for block 10 voltage sensing in the GM document. Its generic circuit-J range/performance label should not be mistaken for a simple low-voltage threshold. The controller is checking relationships between separate measurements.

Both comparison errors must qualify

Twenty times block 10 voltage is compared with total pack voltage. The absolute difference must exceed 70 V, and twenty times block 11 voltage must disagree with the pack by more than the same limit. The table connects those conditions with AND.

The monitor accumulates 160 failing samples in a 170-sample set, using 100 ms sampling. An article or repair estimate that treats one low displayed block value as the entire P0B69 diagnosis leaves out the neighboring comparison and persistence requirement.

Examine the prerequisites before the battery

GM requires valid block 10 input, RUN mode, the specified 12 V supply window and more than 200 ms since contactor closure. Active block low/high codes or the listed pack-voltage faults prevent the rationality test. Resolve the meaning of those companion reports before treating the comparison as independent proof.

Record the two block channels and pack voltage under the same operating conditions. The source does not identify which sensing path is wrong or prove loss of battery capacity. Component decisions require the applicable hybrid service information, and physical high-voltage work should be handled by trained technicians.

Source and applicability

GM 2010 10OBDG10 Hybrid Diagnostics, cited BPCM or hybrid-controller monitor only. Historical calibration values are not universal specifications; no per-code model, engine or hardware fitment has been established. GM PDF, physical page 227.