P02D8: A cylinder 7 learning limit can remain stored at one rail-pressure level

P02D8 means cylinder 7 injector offset learning has reached its minimum boundary. In the cited GM strategy, that is an adaptation-authority result. It does not describe low rail pressure directly or prove an electrical open circuit at the injector.

The result is stored across pressure conditions

Small-quantity learning estimates delivered fuel from rail-pressure drops during controlled injections in eligible fuel-cut operation. Whenever a new energizing-time correction enters the learning map, the monitor compares it with a calibrated lower boundary.

The outcome is retained in a nonvolatile set of status flags covering the rail-pressure levels used for learning. One saturated entry is enough to establish the minimum-authority finding. The source says the condition becomes unset only when every relevant entry is no longer saturated.

Why a single live value may be misleading

A satisfactory correction at the presently observed pressure does not establish that the entire retained map is healthy. Another pressure region can still contain the limiting value. Preserve the learning status and pressure context rather than replacing the stored evidence with one current scan reading.

The authority diagnostic and small-injection management must be enabled; the operation takes the time required to perform the learning sequence. The table gives a calibration variable, not a universal numerical microsecond limit. It therefore supports checking the stored adaptation state and its valid learning opportunities, while leaving component isolation and any reset or relearning procedure to the applicable service information.

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 923; GM PDF, physical page 924.