P0758: Shift solenoid B circuit monitoring has its own qualification

P0758 identifies the monitored electrical path for shift solenoid B in GM's group 09 transmission summary. The hardware check can detect an open circuit, a ground short or a short to voltage. The generic electrical label therefore does not establish which one occurred.

A repeated electrical result is required

The table requires 43 failing counts out of 50 and lists a 4.3-second evaluation. It also qualifies the test with ignition voltage and engine speed sustained above the specified minimum. A test made immediately after startup may not yet have supplied a valid monitoring opportunity.

This code's published trip classification differs from the neighboring solenoid A electrical entry. Do not transfer warning-lamp timing or confirmation expectations from another solenoid simply because the underlying circuit test looks similar.

Circuit integrity and hydraulic performance answer different questions

P0758 does not directly measure clutch application or gear ratio. A shift complaint can accompany an electrical fault, but the summary does not identify a mechanical transmission repair from the code alone. Likewise, a temporarily normal shift does not prove that the circuit is reliable.

Preserve the exact solenoid identifier and companion faults, then use the matching transmission circuit procedure. Verification should establish valid electrical control and completed monitoring under qualified conditions. If a performance code remains afterward, it requires its own diagnosis rather than being assumed to be another description of P0758.

Source and applicability

2009 General Motors diagnostic parameter file 09OBDG09 TRANS Diagnostics.pdf. Section-specific modules and calibrations; no per-code model or engine applicability established. This explanation describes the documented monitor, not a universal repair procedure.

GM diagnostic parameters, PDF page 7.