P045E: low-pressure EGR does not return to its closed default

P045E follows a low-pressure EGR position-performance failure in this GM strategy. After drive removal, it checks whether the valve has returned toward its fully closed default.

A separate return test after P045B

P045B must already be set. The controller allows more than two seconds after driver shutoff for spring return, then treats measured low-pressure EGR position above 30% as the documented stuck-open condition.

The 30% limit is specific to this low-pressure valve monitor. It should not be substituted with the different limit used for the high-pressure EGR return check. It also means “stuck open” does not require the position reading to show fully open.

Timing and feedback decide whether the observation is useful

The diagnostic system must be active and the listed position-sensor, valve and deviation status gate satisfied. Once the error exists, the table applies no further debounce; its task interval is 6.25 ms and reporting is Type A.

For interpretation, retain the P045B history and a valid position reading taken after the return wait. A reading during an intentional open command is not equivalent evidence. Verification should demonstrate the expected default return through an applicable service procedure. The summary does not identify the obstruction or prescribe forcing the mechanism, dismantling it or replacing the complete EGR assembly.

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 1194.