P2383: EGR differential-pressure offset is implausible at key-off

P2383 is a plausibility test of the low-pressure EGR differential-pressure sensor at key-off. It uses the magnitude of an average raw reading, with a failure boundary above 6.00%. This separates it from the high and low electrical-range codes for the same sensing function.

The key-off learning conditions

The offset learning must have completed with at least 50 samples. Electrical-range and intermittent-signal faults must be absent. The table also requires no missing-default-position fault for the exhaust throttle and no relevant low-pressure EGR valve or position-control faults. Its continuation identifies the end-of-trip event as part of the qualification.

There is no additional debounce after the qualified error is present; reporting is Type A, one trip. That does not mean any arbitrary single sensor sample sets the code, because the average and learning prerequisites come first.

How to verify the right event

A normal pressure response with the engine running cannot alone verify this key-off offset test. Record whether learning completed and whether the associated valves reached the states required to make the reference meaningful. If another valve or sensor fault blocks learning, an incomplete result is expected and does not independently condemn the pressure sensor. Use the specified end-of-trip procedure to verify the offset assessment rather than attempting to reproduce it through engine-load changes.

Source and application limits

This explanation covers the cited 2025 GM monitor. Confirm the vehicle and calibration in its service information before applying these limits; inclusion in this file does not establish model compatibility. GM diagnostic parameters, PDF page 1449. GM diagnostic parameters, PDF page 1450.