P07C7: Intermediate speed B low is an average signal-voltage check

P07C7 concerns a low circuit level on intermediate shaft speed sensor B. In the cited GM TCM, this is the even-clutch speed input. The monitor evaluates average signal voltage, rather than declaring that the shaft’s actual rotational speed is too low.

A low signal must persist with valid supply

The boundary is below 980 millivolts, with 20 millivolts of hysteresis and at least 300 milliseconds of confirmation. The VSS2 sensor supply must be above 8.25 and below 10 volts. Battery voltage is separately constrained to above 8.75 and below 18 volts.

Cranking and the STOP key state are excluded. P0882 and P0883 disable the monitor. These requirements separate an input-level problem from an event dominated by an invalid main supply.

Keep average level separate from reported speed

A zero-speed display does not prove the average voltage crossed this threshold, and a nonzero speed display does not independently verify electrical integrity. Preserve the actual input-level evidence and the correct even-clutch channel assignment.

The source gives a continuous eligible monitor and type-A classification but no pinout or component-replacement rule. The installed transmission’s circuit procedure must distinguish the sensor, its signal wiring, supply distribution and controller input. Checking another shaft sensor is not verification of this B-channel fault. A meaningful completion check must retain the proper supply and operating conditions.

Source and applicability

This explanation covers the cited GM monitor, not every vehicle carrying this code. The application-matrix filename does not resolve cleanly to this file, so no model or engine fitment is assigned. GM diagnostic table, PDF page 919.