B.
Operation During Electrical Interruption
PCS1 enable application of two clutches to maintain forward range operation (either third or fifth Range). If power is interrupted while the transmission is operating in reverse or neutral, the transmission defaults to or continues neutral operation. The operator may turn off and restart the engine, and the selector will provide R (Reverse)/N (Neutral)/3 (Third) range capability regardless of the range at the moment of power interruption.
To minimize the impact of an electrical power interruption, 1000 and 2000 Product Families transmissions incorporate control logic that enables the transmission to revert to total hydraulic operation. Providing that there are not any transmission mechanically failed components, the hydraulic system provides a “limp home” mode, providing the there are no mechanically failed components, allowing the operator to drive the vehicle to a service location
Table 5–3 summarizes the default range the transmission will shift to in the event of an electrical interruption. Refer to Section 5–3 for a complete description of the hydraulic circuit during electrical interruption in any range.
If power is interrupted while the transmission is operating in a forward range, the default positions of the shift valves, the selector valve, and normally closed
Table 5–3. Operating Ranges During Electrical Interruption Range Obtained After Electrical Interruption for Manual Selector Position Range When Electrical Interruption Occurs R (with throttle) N 1 2, 3 4, 5 6 Range After Engine Shutdown and Restart
R N N R R N N R
P or N N N N N N N N
OD, D, 2, 1 5th N 1* 3 5 5 5
* Third range after reverse is selected.
1000 and 2000 Product Families Principles of Operation—May 2005
Copyright © 2005 General Motors Corp.
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