P2721: Solenoid D control circuit detects a short to voltage

P2721 reports a short-to-voltage signature in the electrical control circuit for pressure-control solenoid D. The reviewed GM table includes several alternative transmission mappings, so the solenoid letter alone does not locate a universal clutch or connector.

A faster high-circuit decision

The controller monitors voltage outside its permitted range, with a design specification below 0.5 ohm between the signal and controller voltage source. The documented failure time is greater than 0.06 second within a sampling interval greater than 0.13 second.

That short decision window matters for intermittent evidence. A brief high excursion may be relevant even if a later slow scan display appears normal. The impedance specification is not a workshop instruction to measure a powered circuit.

Match the supply and transmission

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

Depending on transmission, the source maps the code to C4, C23467810R, C23468 or the CVT input clutch. These alternatives require confirmation before selecting service information.

Verification should show acceptable electrical behavior in the correct supply state and completion without renewed failure. A circuit-high result does not prove excessive hydraulic pressure or a clutch stuck on; those are different performance claims. The source documents Type A, one-trip behavior and no mandatory component replacement.

Source and applicability

These limits describe the stated monitor and require vehicle, hardware and calibration confirmation. GM diagnostic table, PDF page 1175.