P2148: Injector 1 remains electrically high when its driver is off

P2148 describes a short-to-power diagnosis on injector 1's high-side circuit in the reviewed GM source. The broader dictionary name refers to injector group A supply voltage high. Confirm that this injector-number mapping belongs to the vehicle's calibration before using it to choose a circuit.

Command state is the key distinction

The controller performs this check while the output is powered off. It detects driver voltage outside the accepted off-state range. A high signal during a legitimate injector command is therefore not the same evidence as voltage remaining high when that driver should be off.

The table's controller specification is a signal within one volt of controller power for the short-to-power condition. This describes the fault signature; it is not a universal injector operating-voltage specification.

Evidence to preserve

The diagnostic requires battery voltage of at least 11 V and excludes the listed P062B failure states. Ten failed samples in a 20-sample window, at 100 milliseconds per sample, establish the fault. Retain battery voltage and commanded driver state along with the circuit observation when investigating an intermittent event.

Because this monitor evaluates electrical behavior, it cannot establish that injector 1 is leaking fuel or mechanically stuck open. Those are different claims requiring different evidence. After an identified circuit fault is repaired, verification should include acceptable off-state response under the applicable service test and no recurrence when the diagnostic completes. The source lists Type A, one-trip behavior.

Source and applicability

The thresholds and component mapping apply only to the documented monitor, pending vehicle and calibration confirmation. GM diagnostic table, PDF page 604.