Solenoid Switch Valve

DESCRIPTION
The Solenoid Switch Valve (SSV) is located in the valve body controls the direction of the transmission fluid when the L/R-TCC solenoid is energized.

OPERATION
The Solenoid Switch Valve controls line pressure from the LR-TCC solenoid. In 1st gear, the SSV will be in the downshifted position, thus directing fluid to the L/R clutch circuit. In 2nd, 3rd, and 4th, it will be in the upshifted position and directs the fluid into the Torque Converter Clutch (TCC) circuit.
When shifting into 1st gear, a special hydraulic sequence is performed to ensure SSV movement into the downshifted position. The L/R pressure switch is monitored to confirm SSV movement. If the movement is not confirmed (the L/R pressure switch does not close), 2nd gear is substituted for 1st. A DTC will be set after three unsuccessful attempts are made to get into 1st gear in one given key start.

ELECTRONICALLY MODULATED CONVERTER CLUTCH
Torque Converter Clutch (TCC) operation is controlled by the Transmission Control Module (TCM) through the solenoid and pressure switch assembly and valve body. When the transaxle is in 2nd, 3rd, or 4th gear, the Torque Converter Clutch (TCC) can be energized when certain conditions are met.
In order to reduce heat build-up in the transmission and buffer the powertrain against torsional vibrations, the TCM can duty cycle the L/R-CC Solenoid to achieve a smooth application of the torque converter clutch. This function, referred to as Electronically Modulated Converter Clutch (EMCC) can occur at various times depending on the following variables:
- Shift lever position
- Current gear range
- Transmission fluid temperature
- Engine coolant temperature
- Input speed
- Throttle angle
- Engine speed
The TCM controls the torque converter by way of internal logic software. The programming of the software provides the TCM with fine control over the L/R-CC Solenoid. There are four output logic states that can be applied as follows:
- No EMCC
- Partial EMCC
- Full EMCC
- Gradual-to-no EMCC

NO EMCC
Under No Electronically Modulated Converter Clutch (EMCC) conditions, the L/R Solenoid is OFF. There are several conditions that can result in NO EMCC operations. No EMCC can be initiated due to a fault in the transaxle or because the Transmission Control Module (TCM) does not see the need for EMCC under current driving conditions.

PARTIAL EMCC
Partial Electronically Modulated Converter Clutch (EMCC) operation modulates the L/R Solenoid (duty cycle) to obtain partial torque converter clutch application. Partial EMCC operation is maintained until Full EMCC is called for an actuated. During Partial EMCC some slip does occur. Partial EMCC will usually occur at low speeds, low load and light throttle situations.

FULL EMCC
During Full Electronically Modulated Converter Clutch (EMCC) operation, the Transmission Control Module (TCM0 increases the L/R Solenoid duty cycle to full ON after Partial EMCC control brings the engine speed within the desired slip range of transaxle input speed relative to engine rpm.

GRADUAL-TO-NO EMCC
This operation is to soften the change from Full or Partial Electronically Modulated Converter Clutch (EMCC) to No EMCC. This is done at midthrottle by decreasing the L/R Solenoid duty cycle.

SHIFTER/IGNITION INTERLOCK
The ignition interlock system connects the automatic transmission shifter and the ignition lock system. With the ignition key in the LOCK or ACCESSORY position, the interlock system prevents the transmission from being shifted out of park.
When the key is in the OFF or RUN position the shifter unlocks and can be moved to any gear position. The system also prevents the operator from turning the ignition key to the LOCK or ACCESSORY positions.

NOTE:
- If the vehicle has column shift, install a new interlock cassette (column shift) when replacing the ignition lock cylinder. Adjust the system after replacing the cassette..
- If the vehicle has floor shift, adjust the interlock cable after replacing the lock cylinder.