Diagnostic article Generic OBD-II
P0639: bank-2 throttle effort and supply-voltage compensation
P0639 evaluates bank-2 throttle-actuator duty-cycle range in the source.
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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.
P0639 evaluates bank-2 throttle-actuator duty-cycle range in the source. It uses the absolute duty magnitude, meaning the diagnostic concerns how much control effort is commanded rather than assigning a particular movement direction.
The limit is calculated
The table takes the minimum of 95 percent and a compensated value equal to 80 percent times 13.5 volts divided by measured battery voltage. Battery voltage therefore participates in the acceptance limit. Comparing a duty value with a fixed 80-percent rule at every voltage would misstate the monitor.
Eligible operation includes drive or post-drive state, an enabled actuator power stage, valid actual position, no adaptation release, and a constrained desired-position gradient. The row lists a 0.6001-second detection interval and one-trip reporting.
Use bank-2 control data
A correct position does not necessarily mean normal effort: the controller may reach that position while commanding excessive duty. Conversely, an ordinary high-effort transient outside the qualified gradient state is not automatically the same failure.
Verification should retain bank-2 duty, supply voltage, position validity, and diagnostic execution status together. The source establishes the range check but does not determine whether resistance to motion, an electrical issue, or another vehicle-specific condition caused it. Correct channel mapping is required before using bank-1 data as comparison evidence.
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
Throttle Actuator Control Range/Performance Bank 2
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