If for any reason the entire electronic control system of the transmission become disabled, all five of the shift solenoid valves will be de-energized (OFF). This EMERGENCY MODE operating state of the solenoids forces the transmission to operate in Fifth gear regardless of other vehicle operating conditions when the gear selector lever is in a forward range. Also, in EMERGENCY MODE, the lock up pressure control solenoid valve is turned OFF in order to prevent TCC apply. This allows the vehicle to be operated safely, despite the disabled controls, until the condition can be corrected.
If EMERGENCY MODE is enabled while the transmission is operating in DRIVE Range, the transmission will assume a Fifth gear hydraulic power flow state with the following exceptions.
The 3-4, 4-5 SS valve assembly is de-energized, allowing fluid pressure in the S4 signal (17) fluid circuit to exhaust through the solenoid.
45 enable (51) fluid pressure exhausts from the solenoid relay valve, passes through the U2 shift valve into the S4 signal (17) fluid circuit and continues on to the 3-4, 4-5 SS valve assembly where it exhausts into the sump.
The lock up pressure control solenoid valve is de-energized, allowing lock up control (12) fluid and TCC signal (13) fluid to exhaust through the solenoid.