Diagnostic article Generic OBD-II
P2077: The tuning position low-range test uses a bounded raw-voltage window
Learn the supported GM P2077 voltage criterion and why signal format and enable state must be identified before interpreting a low position reading.
Read before applying this article
Documented application
2025 GM 07A-1 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.
P2077 identifies a low intake manifold tuning-valve position signal on bank 1. The GM row assesses the raw position-sensor voltage, rather than declaring that the valve is physically stuck at its closed stop. Electrical range and actual valve motion remain separate questions.
The documented low region is not every zero-like reading
The failure condition is raw voltage below 0.7 V while still greater than zero. The source therefore describes a bounded low region; this article does not extend it to every missing, zero or invalid signal state without further documentation.
Battery voltage must be above 9 V and below 17.5 V, and the listed evaluation is 0.05 second with two-trip reporting. The enable block also references ADC, PWM and SENT feedback configurations. The applicable architecture must be established rather than assuming that a voltage test transfers unchanged to every possible interface.
Keep the raw signal distinct from decoded position
Preserve the configured feedback type, raw measurement and monitor status. A displayed valve angle may already be scaled or substituted by the controller, so it cannot automatically stand in for the raw voltage used in this row.
The source supplies neither a connector pinout nor a definitive physical-stop mapping for the low region. It cannot identify a failed position sensor, wiring path or actuator from P2077 alone. The correct tuning-valve service information is needed before selecting a circuit test or mechanical repair.
Source and applicability
2025 GM 07A-1 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 931; GM PDF, physical page 932.
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
Intake Manifold Tuning (IMT) Valve Position Sensor/Switch Circuit Low Bank 1
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