GM Service Manual Online
For 1990-2009 cars only

Check

Causes

DEFINITION: The transmission only provides first gear in Drive range. The vehicle accelerates from a stop in first gear and does not upshift.

Control Valve Body Accumulator Assembly

    • 1-2 shift control valve stuck applied
    • 1-2 shift valve stuck applied

Control Valve Body Accumulator Assembly

The spacer plate or gasket are mispositioned or damaged

Shift Solenoid Valve

    • Stuck or damaged
    • Faulty electrical connection