P26E5: Low pinion-relay feedback uses its own starting-voltage boundary

P26E5 concerns the starter pinion-relay high-side output being classified as shorted to ground while the output is on. The GM row evaluates controller-specific voltage feedback. It is not a direct measurement of pinion movement or evidence that the starter mechanism is mechanically locked.

The enable voltage differs from related codes

This monitor permits run/crank voltage down to 6.41 V. The neighboring open- and high-circuit rows use an 11 V minimum. Importing their eligibility into P26E5 would therefore change when this particular diagnosis can run.

The documented electrical classification corresponds to impedance at or below 0.5 Ω toward controller ground. Because this describes the internal diagnostic model, it cannot be used as a connector resistance specification without the applicable circuit information.

Separate fast confirmation from mechanical conclusions

P26E5 uses eight failures out of ten samples, with 50 ms per sample. That sample decision is shorter than the 40-of-50 checks printed for the adjacent open and high faults. The two-trip reporting classification is a separate matter from these sampling intervals.

Retain output command, supply voltage and the exact subtype when evaluating a starting complaint. A normal signal after the command ends does not test the same state. The monitor provides an electrical direction for investigation but does not locate a ground path or prove that the relay, harness or controller requires replacement.

Source and applicability

2025 GM 25OBDG03B documented monitor only. Vehicle, engine and calibration applicability must be confirmed from the matching service information; no model fitment is inferred. These criteria explain controller logic, not a complete repair procedure. 25OBDG03B, PDF page 853. 25OBDG03B, PDF page 854. 25OBDG03B, PDF page 855.