P0C84: Sensor H high circuit can produce a cold limit reading

P0C84 is the high-circuit diagnostic for battery-temperature sensor H in the cited GM controller. The table's explicit condition is a temperature report below −40°C with ADC count above 3992. Electrical high and physical high temperature are not interchangeable descriptions.

Keep the conversion relationship visible

An extreme cold report may arise from the signal path represented by the ADC value. This code alone cannot distinguish a physical temperature condition from an inaccurate measurement. Preserve the original reading and related electrical faults for the diagnostic technician.

The controller requires 1.4 seconds of failure within a two-second window at 200-millisecond intervals. The pass row requires at least −40°C and ADC no greater than 3992 for two seconds. One normal sample after the event does not cover that recovery interval.

Verify the monitor's prerequisites

The shared source excludes specified communication, reference-voltage, internal-performance and bus-off faults. Enabled communication and an inactive secondary protection self-test are required. If those conditions block evaluation, no fresh code is not evidence of a passed H circuit.

The strategy sentence's temperature-direction wording conflicts with the explicit limit, which is flagged for review. No missing correction is invented. The H designation must be mapped through the exact battery documentation, and physical high-voltage work belongs to trained personnel following the appropriate vehicle service procedure.

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 639 · GM source, physical page 640.