P2738: Solenoid F electrical path indicates a short to ground

P2738 identifies a ground-short signature in pressure-control solenoid F's circuit in the reviewed GM transmission monitor. The electrical result should not be confused with low line pressure: the code refers to the circuit voltage, not a hydraulic measurement.

Transmission type changes what the circuit controls

The source maps F to 9-speed C6789/SOWC CBR1, 10-speed C45678910R, 8-speed line-pressure control, or the CVT binary pump. The correct function needs confirmation before interpreting any accompanying pressure or clutch symptoms.

The driver design criterion is less than 0.5 ohm between signal and controller ground. Failure must exceed 0.30 second within a sample period exceeding 0.50 second, at a 6.25-millisecond update rate. These figures describe the controller's decision rather than a safe manual test procedure.

Supply availability affects interpretation

Battery voltage must be above 9 V and below 32 V for more than one second. The appropriate run/crank or accessory condition must be present, and the mapped high-side driver must be on.

A low reading from an intentionally unsupplied path does not automatically reproduce the fault. Retain driver status when examining the circuit, and use the applicable electrical procedure to distinguish the load, wiring and controller output.

Verification should establish acceptable circuit behavior in its enabled state and no recurrence after monitor completion. The source documents Type A, one-trip behavior but does not prove mechanical transmission damage or require replacement of the solenoid or valve body.

Source and applicability

Keep the stated transmission function and source calibration separate from other applications. GM diagnostic table, PDF page 1192.