P045A: low-pressure EGR command circuit open-load evidence

The documented P045A monitor tests low-pressure EGR actuator commands for an open circuit. Hardware feedback reports a load resistance above 200 kilohms with the H-bridge driver off.

The default position changes the test context

The valve must be requested away from its fully closed default. An unpowered valve resting closed does not, by itself, satisfy the diagnostic observation. The test combines command context with the electrical loading reported by the hardware.

Cranking must have ended, relay supply must exceed 11 V and the hardware error status must be determinate. Diagnostics must be enabled. The table filters 240 failures among 300 samples on a 12.5 ms task and uses Type A, one-trip reporting.

Useful diagnostic distinctions

An open-load indication concerns the actuator's electrical path; it does not directly measure low-pressure EGR gas flow. Likewise, a valve position error without open-load evidence cannot be assumed to have the same electrical explanation.

For verification, establish that the appropriate request away from default occurred and that the off-state hardware check reports normal loading. Treat the resistance number as a controller threshold, not an instruction to use an ohmmeter on an energized circuit. The page provides no proof of which connection, actuator element or controller circuit is responsible. Follow the applicable vehicle procedure to isolate the open path before selecting a repair.

Source and applicability

2025 GM 25OBDG04B diagnostic parameter tables; the cited monitor only. Vehicle, engine and calibration applicability must be confirmed separately. These tables describe detection logic, not a complete repair procedure or a component replacement verdict. gm-2025-04b, PDF page 1189.