GM Service Manual Online
For 1990-2009 cars only

Inaccurate/Inconsistent Shift Points

Checks

Causes

Shift Solenoids (305)

    â€¢ Contamination
    â€¢ An intermittent open or a shorted circuit

Throttle Position Sensor

    â€¢ Damaged, disconnected
    â€¢ An intermittent open or a shorted circuit

Vehicle (62) and Input Speed Sensors (46)

    â€¢ Damaged, disconnected or loose
    â€¢ An intermittent open or a shorted circuit