P02D0: cylinder 3 correction below the SQP learning floor

P02D0 is the cylinder-3 minimum-authority result in the cited SQP injector monitor. The controller checks the learned energizing-time adjustment against a lower calibration limit whenever it updates the learning map.

Follow the quantity estimate

SQP stands for a small-quantity adjustment based on rail-pressure drop. During diesel fuel cut-off it commands a small injection, observes the pressure change and estimates delivered quantity. Consequently, this code describes the learning system's conclusion; it does not directly report a measured injector resistance or a mechanical blockage.

The threshold is expressed in microseconds and remains calibration-specific. A generic numeric “acceptable injector offset” would not be supported by this page.

Interpret persistence correctly

Saturation is stored for the various SQP rail-pressure levels. Any one true saturation flag can set the condition, and all must be false for the source's unset criterion. A healthy result from one operating region cannot establish that every stored entry has recovered.

Check the availability and completion of cylinder-3 learning with SQP injection management enabled before treating a quiet drive as verification. The table gives one sample per cylinder firing event during the learning process and Type B reporting over two trips. These are detection characteristics, not a guarantee of how quickly any particular vehicle will relearn. Professional fuel-system diagnosis must use the correct calibration and service information.

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 1145.