Actron GM Code Scanner CP9001 - Manual (Page 32)

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conditions. This improves fuel
economy by eliminating power loss in
the torque convertor. The computer
energizes a solenoid to achieve lock-
up. Signals from the engine coolant
temperature, throttle position and
vehicle speed sensors are used.
• Transmission Control
Some transmissions have computer
controlled shifting. Two solenoids
mounted in the transmission are
energized singly, or in combination, to
select a gear ratio. The solenoids
direct the flow of fluid within the
transmission to cause the shift. The
computer uses throttle position,
vehicle speed, engine loading and
other sensor information to determine
the optimum shift performance. The
computer can also set the shift quality
- anywhere from harsh to smooth. This
is done using a “force motor” actuator
in the transmission to adjust the
internal fluid line pressure.
More information
The Glossary (Section 8) describes
various sensors and actuators used in
computer controlled engine systems.
You can learn more by reading these
definitions.