P06DD: two-stage oil-pump response remains in the high-pressure state

P06DD is a performance fault in the cited two-stage oil-pump strategy. The documented implementation diagnoses a pump remaining in its high-pressure state when the control sequence should produce a change. This is more specific than assuming the generic stuck-off wording means low oil pressure.

Pressure change and pressure level work together

The intrusive test cycles the control off for high pressure and on for low pressure. It compares filtered pressure at the beginning of a state change with the value 1.5 seconds later. Too little change alone is not the complete failure decision: measured pressure must also support the high-state classification.

The displayed decision requires more than twelve errors out of fifteen samples. Actual pressure-change and level thresholds are referenced to supporting tables, so no universal kPa limit is asserted here.

Passing once does not end all monitoring

After the intrusive test passes, a passive test watches ordinary control transitions. An inadequate response can trigger the intrusive sequence again. A later recurrence therefore need not contradict an earlier successful test.

Prerequisites include the two-stage system being present, more than ten seconds of running, sufficient ambient pressure and valid related sensor information. The source also excludes an oil-aeration condition. Use the exact professional procedure to evaluate command, pressure response and prerequisites together. This article does not authorize forcing oil-pump modes or infer adequate lubrication from the code's high-state classification.

Source and applicability

Documented monitors in gm-2025-03a, model year 2025. These are module/calibration examples; vehicle, engine and transmission applicability must be confirmed independently. GM 2025-03a, page 430.