Diagnostic article Generic OBD-II
P284E: Repeated rod-two corrections can explain an unrequested-movement code
P284E includes correction-count and correction-duration routes as well as a direct rod-two drift comparison.
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Documented application
2025 GM 25OBDG07A Part 2 documented monitor only; its application-matrix filename join is unresolved. No model, engine or universal calibration applicability is inferred.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P284E identifies rod-two drift in the cited controller. The direct check compares measured position with the allowable band for the logically engaged gear, using speed evidence to confirm that gear state. It requires no rod force and excludes position-sensor faults, active shifts and learning routines.
A returned position does not erase the evidence
The controller also counts drift-correction activations. At least ten activations, or more than five seconds of active correction, can produce a fault. Correction is triggered at narrower limits than the direct wide-band test. A position that appears acceptable after correction may therefore coexist with a legitimate drift record.
The direct out-of-band route has a 500 ms confirmation period and requires the odd-clutch/output-speed context documented for this rod.
Verification must include correction history
Preserve the correction count and duration alongside rod-two position and validated gear state. Looking only for a large final displacement can miss a problem the controller repeatedly counteracted. Do not invent the learned position limits from another transmission or rod. The source establishes a control-system drift finding; it does not identify the particular mechanical, hydraulic or sensing cause without the applicable vehicle service procedure.
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.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Shift Fork B Unrequested Movement
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT