P0202: An electrical opening in the cylinder 2 injector path

The documented GM P0202 diagnostic addresses an open circuit in the cylinder 2 direct-injection output path. It is not a combustion-balance test. The controller uses its driver's voltage feedback to recognize an electrical load condition outside the acceptable range.

Why on and off measurements differ

The low-side portion is checked with the output powered off, while a high-side alternative is checked with the output powered on. Those different states are part of the monitor design. Comparing a voltage captured in the wrong driver state with an assumed fixed limit can therefore lead to the wrong conclusion.

The published driver specification uses an open-circuit impedance boundary of at least 200 kΩ. It gives no universal pin-to-pin workshop method. Vehicle-specific circuit information remains necessary to identify the correct test points and controller architecture.

Preserve evidence beyond the cylinder number

The monitor runs with battery voltage at or above 11 volts and appropriate P062B status. Its failure counter requires ten of twenty samples at a 100-millisecond interval. Record whether P0202 is isolated or accompanies wider injector-control faults, since a broader driver issue changes how the cylinder-specific feedback should be interpreted.

A valid repair confirmation is a completed electrical monitor with the cylinder 2 driver responding correctly. Smooth running alone does not reproduce both driver-state checks. Use the approved direct-injection service procedure for any electrical or fuel-system intervention.

Source and applicability

This explanation is limited to the 2025 GM 25OBDG03A monitor on page 211. Its thresholds are calibration examples, not universal specifications. Confirm the vehicle, engine and controller procedure before applying them.