Diagnostic article Generic OBD-II
P2C48: Coolant-pump performance is inferred from phase-current behavior
Understand how P2C48 compares pump current with an expected model rather than directly measuring coolant flow.
Read before applying this article
Documented application
2025 GM 25OBDG04A documented monitor only. Vehicle, engine and calibration applicability must be confirmed from the matching service information; no model fitment 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.
P2C48 concerns the low-temperature coolant-loop pump’s performance in the cited GM system. The monitor supervises phase current against an expected-current model related to pump speed. Its flow-deviation description should not be mistaken for a direct measurement from a coolant-flow sensor.
Compare current under the required speed conditions
The failure criterion is an absolute phase-current error above 1 A for more than five seconds. Actual pump speed must exceed 2,800 rpm. A current reading gathered at low speed therefore does not reproduce the stated performance check.
The source also requires pump enablement, valid current-related diagnostics, supply and coolant-temperature eligibility, and no cranking. Ten failed observations out of twelve samples are specified at one-second sampling. That sample rule and the current-error persistence condition should not be casually added into an invented universal timer.
Recognize what the current model does not disclose
The supporting table labels speed as its horizontal input but leaves its additional row dimension unlabeled. It therefore cannot be used to reconstruct every expected-current value confidently from this summary alone.
Retain speed, measured current, available expected-current data and enable state together. The code supports investigating a mismatch with the pump model, not automatically diagnosing a blockage or replacing the pump. Confirm the actual model inputs and vehicle procedure before assigning a mechanical cause.
Source and applicability
2025 GM 25OBDG04A documented monitor only. Vehicle, engine and calibration applicability must be confirmed from the matching service information; no model fitment is inferred. These criteria explain controller logic, not a complete repair procedure. 25OBDG04A, PDF page 670. 25OBDG04A, PDF page 1274.
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
Coolant Pump C Control Circuit Performance/Stuck Off
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