P245C: EGR cooler bypass circuit low and H-bridge overcurrent

P245C identifies a ground-short classification in the high-pressure EGR cooler bypass valve motor control circuit in this GM table. The monitored component is the DC motor and its H-bridge driver. This is an electrical output diagnosis; the row does not evaluate whether exhaust gas actually passes through the cooler.

What makes the monitor fail

The controller receives hardware input/output error information when current through the H-bridge switches exceeds 8 A. The driver must be on. The decision requires 160 failed samples within 200 samples, with a 12.5 ms function task; the table assigns Type B, two-trip behavior. An isolated current spike is therefore different from the qualifying accumulated failure.

There are additional gates: the engine must be out of cranking, powertrain relay supply must exceed 11 V, the diagnostic system must be enabled, and the hardware error status cannot be indeterminate. Clearing codes or an end-of-test operation can prevent this monitor from evaluating the circuit normally.

Distinguishing the useful evidence

Capture the bypass command, available driver fault classification, supply voltage and related EGR codes together. The high-circuit companion monitor uses the same current threshold, so current alone cannot establish whether the path is shorted toward ground or power. The reported hardware classification matters.

A stuck valve hypothesis needs position or mechanical evidence beyond P245C. Similarly, a fault that disappears with the motor uncommanded has not necessarily passed this on-state check. Use the correct vehicle wiring and actuator test procedure to identify the affected motor circuit before deciding whether wiring, connections or the actuator requires repair.

Source and applicability

2025 GM 04A documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file. GM PDF, physical page 1193.