Diagnostic article Generic OBD-II
P0343: bank-1 intake cam signal stops at a high level
P0343 detects loss of new signal edges from the bank-1 intake camshaft sensor while its signal remains high.
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Documented application
2025 GM 25OBDG07A Part2 diagnostic monitor documentation; the application-matrix filename mismatch is unresolved, so no model or engine 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.
P0343 detects loss of new signal edges from the bank-1 intake camshaft sensor while its signal remains high. The documented monitor uses crankshaft rotation to decide that expected camshaft information is missing.
High level alone is not the complete fault
The table requires at least four crankshaft revolutions and a permanently high signal at transition into the no-signal state. Ignition must be on, a crankshaft signal with its gap must be detected, and reverse engine rotation must not be detected.
A high logic level can occur normally within a changing digital waveform. What makes this condition diagnostic is the absence of expected new edges over the qualified rotation interval. The four-revolution criterion also is not a fixed number of seconds.
What to verify
Preserve crankshaft synchronization and camshaft-edge information together. If the crankshaft reference is not valid, an observation of a static cam signal does not reproduce the listed prerequisites. If edges return later, their presence alone does not erase the earlier missing-edge interval.
The source lists one-trip reporting plus common enables and inhibitors. Verification should show the bank-1 intake signal producing the required edges while the reference and rotation conditions are valid. The code does not by itself establish mechanical timing displacement or prove a defective sensor.
Documentation and applicability
These details describe the monitor in GM’s 2025 25OBDG07A Part2 file. Its application-matrix filename does not match the download index, so model and engine applicability remain unresolved. Use the vehicle’s correct service information before applying these calibration details.
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
Camshaft Position Sensor A Circuit High Bank 1 or Single Sensor
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