P026E: cooler coolant pump current disagrees with its speed model

P026E monitors charge-air-cooler coolant-pump performance indirectly through electrical load. The ECM estimates expected pump AC phase current from actual pump speed, then compares it with measured phase current. An absolute current error above 5 A for more than five seconds is the stated deviation criterion.

It is not a direct flow-meter reading

The source describes the result as a flow-deviation failure, but its evidence is current versus a speed-based expectation. The code alone cannot establish a measured coolant-flow rate, locate a restriction or prove that the impeller failed.

The pump hardware must be present, the diagnostic enabled and actual speed above 1,000 rpm. Current-range fault status, supply configuration, coolant-temperature gates and related communication faults also affect eligibility. The engine must not be cranking and the pump must be enabled.

Two timing details are listed

The row includes the more-than-five-second deviation condition and a decision of sixteen failures out of twenty samples at one second per sample. Those describe separate parts of the evaluation and should not be collapsed into a single five-second timer. Reporting is Type A, one trip.

Preserve actual speed, expected/measured current and validity status together. Verification requires agreement during eligible pump operation, followed by any needed cooling-performance checks. The table provides no safe coolant-opening, pump-bypass or replacement procedure.

Source and applicability

GM 04B, PDF page 481. This explanation covers the documented 2025 monitor. Confirm the vehicle's module, engine and calibration before applying these criteria; the document's vehicle list does not establish this code's applicability to every listed model.