P049E: low-pressure EGR endpoint learning exceeds permitted limits

P049E checks the learned endpoint offsets of the low-pressure EGR SENT position sensor. This strategy can assess the fully closed position, the fully open position or both during key-off learning.

Identify which endpoint failed

The closed-position window is bounded by failure below 6.80% or above 12.70% of the 5 V scale. The open-position boundaries are below 84.40% or above 96.20%. The code alone does not tell which endpoint exceeded its window, so preserving endpoint-specific learning data changes the diagnostic interpretation.

These are learning limits rather than simple circuit-validity limits. A sensor may report values inside its broad electrical range while its learned stop offsets are unacceptable.

Learning must complete under valid conditions

The table requires coolant between 30°C and 150°C, outside air at least −20°C, valid temperature inputs and battery voltage at least 9.50 V for closed-loop control. Key-off learning must complete, the end-of-trip event must have elapsed and diagnostics must be enabled.

A normal valve-angle reading during engine operation does not verify those endpoints. Confirmation should use the applicable learning procedure and establish acceptable results at the endpoint or endpoints being assessed. The source lists immediate reporting once the error exists, without added debounce, but it provides no instruction to alter stops, force the valve or select a replacement component.

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 1207; gm-2025-04b, PDF page 1208.