Diagnostic article Generic OBD-II
P07B4: Park-button switch A high-signal qualification
P07B4 detects repeated high readings from Park-button switch A in the reviewed GM implementation.
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Documented application
Documented 2025 GM diagnostic parameter monitor in 25OBDG04B.pdf; model, engine and calibration applicability require vehicle-specific confirmation.
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.
The GM source for P07B4 monitors the Park pushbutton's switch A electrical signal. “Circuit high” describes that input's measured range. It does not mean that Park is necessarily engaged, nor does it establish a mechanical parking-lock defect.
A signal value, not a published voltage
The table places the high boundary at 236.00 or greater. No unit is printed for the number. It should remain a controller-signal threshold rather than being converted into an invented voltage specification. Before comparing scan data with it, establish how the diagnostic tool represents this input.
The failure counter needs 20 high samples out of 25, with the software operating on a 25-millisecond loop. The listed reporting policy is Type B across two trips. This sample requirement distinguishes a qualified high condition from an isolated excursion that may be visible in a trace.
Separating input and engagement evidence
A displayed selector request and the actual switch A electrical measurement answer different questions. The former can show a requested mode; P07B4's documented evidence concerns the latter. Preserve both if available, and verify calibration enablement before treating a no-code observation as a successful test.
After the underlying issue is addressed, confirmation should exercise the Park-button input and establish that the high-range counter no longer qualifies under the applicable diagnostic. The source does not specify a connector test or justify replacing the complete shifter. The explanation is limited to this 2025 GM parameter-file row, with exact vehicle coverage still requiring service confirmation.
Source: GM monitor, PDF page 647.
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
Transmission Park Position Sensor/Switch A 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