Normal Operation

Normal Operation Of 1999 4L30-E Transmission
Torque Converter Clutch (TCC) Application Conditions:
The TCC is normally applied in 2nd, 3rd and 4th gears only when all of the following conditions exist:
^ The engine coolant temperature is above 70°C (158°F).
^ The brake pedal is released.
^ The shift pattern requests TCC apply.
Moreover, TCC is always applied in 2nd, 3rd and 4th gears when the transmission oil temperature is above 135°C (275°F).
This mode should be canceled at 125°C (257°F).

ATF Warning Lamp
The ATF warning lamp will be constantly on (not flashing) if the transmission oil temperature is above 145°C (293° F).
The ATF warning lamp goes off again when the transmission oil temperature is below 125°C (257°F).

Special Shift Pattern When The Engine Is Cold:
A special shift pattern is activated when the engine coolant temperature is below 70°C (158°F). (3-4 shifts, for example, are delayed for small throttle openings and will occur a few MPH higher.)