Shift Indicator - A/T: Description and Operation

FIRST TO FOURTH GEAR SHIFT INDICATOR LAMP - PCM OUTPUT
The PCM operates the first gear to fourth gear shift lamp. The lamp informs the driver to shift into fourth gear on the next transmission upshift. The PCM illuminates the shift lamp when the following conditions have been met:
- Vehicle speed between 12 - 18 mph
- Transmission in first gear
- Engine speed greater than 608 rpm
- Throttle position less than 23 percent (less than 0.68 volts over closed throttle TPS voltage)
- Coolant temperature above 41 °C (106 °F)