Diagnostic article Generic OBD-II
P2843: Rod-four circuit high has two distinct digital-signal routes
P2843 checks a pulse-free high input or duty cycle above its limit, with reference-supply eligibility explicitly unresolved.
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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.
P2843 concerns rod-four position feedback in the cited transmission. The source detects either no pulses with the input above 3.5 V or duty cycle above 92%. It lists a 150 ms confirmation interval. Neither branch is a direct claim that the mechanical fork is too high or has travelled too far.
Distinguish a static line from a distorted pulse train
The first route needs missing transitions as well as the high electrical state. The second can fail even while pulses continue. A single voltage sample or averaged reading cannot reliably identify which pattern occurred.
The VREF2 enable fields in this source print above 5.5 V and below 4.5 V simultaneously. That contradiction remains flagged, with no assumed reversal of the limits. The inhibit list includes P0652/P0653 and P0882/P0883.
Verification preserves channel and supply context
Record rod-four pulse activity, duty cycle and reference-supply status together. A later normal position display does not prove the original waveform was valid. Use the vehicle’s calibration-specific service information to resolve supply eligibility and the permitted test method. The code classifies an electrical symptom but cannot alone identify the sensor, harness or controller input as the failed part.
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 D Position Circuit High
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