P216C: A group E high result compares an off-state signal with its power source

P216C identifies a high injector group E supply-circuit condition. The cited GM monitor calls this injector 5's high-side output and tests it while the driver is off. An output remaining too close to controller power is classified as a short toward power.

Voltage reference matters as much as magnitude

The source's electrical criterion is a signal-to-controller-power difference no greater than one volt. It is not a one-volt threshold referenced to ground. A trace showing only absolute output voltage can therefore omit the reference needed to interpret the documented comparison.

The assessment also needs battery voltage of at least 11 V and the specified P062B failure states to be absent. Ten failed samples within twenty are collected on a 100-millisecond task, followed by one-trip reporting.

Verify the expected off behavior

Preserve the command, signal and power reference during the event. A high signal during an intentional on command does not demonstrate the off-state fault. Similarly, a later normal output cannot establish what happened during the qualifying sample history.

The generic group-E designation does not independently locate injector 5 on an unspecified engine or prove which connected part failed. The monitor identifies electrical behavior without distinguishing the load, harness and output-stage causes. Use the actual circuit layout and service procedure before selecting a replacement or interpreting this code as excessive injected fuel.

Source and applicability

2025 GM 06B 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 440.