P283D: Rod-three circuit low must be read with its reference-supply status

For P283D, the monitored digital input belongs to rod-three position feedback. The controller accepts either no pulses with the pin below 2 V or duty cycle below 8% as electrical-low evidence. A low phase within an otherwise valid pulse train is not sufficient by itself.

The reference circuit changes with the channel

This row uses VREF2, with P0652 and P0653 among the inhibit codes, rather than the VREF1-related faults used for earlier rods. That distinction can matter when several position codes accompany a shared supply problem.

The source nevertheless prints mutually incompatible VREF2 enable limits, above 5.5 V and below 4.5 V. Exact numerical eligibility is unresolved here; the values are not silently reversed. The signal-fault confirmation interval is at least 150 ms.

Preserve electrical evidence first

Keep pulse presence, duty cycle and reference-supply diagnostics with the event. A mechanical position complaint does not reproduce this digital-signal check, and an average voltage may hide pulse behavior. Applicable service information must resolve the enable conflict and identify the actual circuit. The DTC alone does not prove that the position sensor, connected wiring or controller input has failed.

Document scope and source

2025 GM 25OBDG07A Part 2 documented monitor only; its application-matrix filename join is unresolved. No model, engine or universal calibration applicability is inferred. These figures explain the cited controller logic, not a vehicle-specific repair instruction. Match the vehicle’s service information before applying them.

GM physical PDF page 914.