Diagnostic article Generic OBD-II
P0726: Engine-speed performance includes jump, noise and coupling checks
Understand the separate GM P0726 performance branches and the incomplete counter thresholds that limit a literal reproduction from this summary.
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Documented application
2025 GM 06B documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file.
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.
P0726 is an engine-speed input range/performance code. The cited GM transmission monitor distinguishes a large speed change, a noisy signal and a possible coupling-related pattern. Those branches are more specific than a generic instruction to replace an engine-speed sensor.
Separate a jump from repeated noise
One branch detects a speed change of at least 600 rpm persisting for at least 0.15 second. Another evaluates eighty samples, incrementing separate counters for sufficiently large negative and positive changes. An isolated step and alternating excursions therefore contribute different evidence.
The noisy-signal row gives the positive and negative increment boundaries but does not display complete final counter comparisons. The coupling-related branch also contains incomplete conditions. This article does not fill those gaps with invented counter limits or claim to reproduce every branch numerically.
Preserve the sequence and enabling fault status
A useful record includes the speed trace over time and which performance branch reported the fault. A smoothed average can conceal the excursions relevant to the noise assessment. Existing input-speed faults and per-key-cycle diagnostic states also affect the listed eligibility conditions.
The diagnostic task runs every 20 milliseconds and uses two-trip reporting, while individual branches have their own timing. The source supports distinguishing these signal patterns but cannot identify the exact electrical cause, establish a physical sensor location or justify a replacement without the matching transmission diagnostic procedure.
Source and applicability
2025 GM 06B documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file. GM PDF, physical page 744; GM PDF, physical page 745.
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
Engine Speed Input Circuit Range/Performance
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