The auto transmission won't shift into overdrive when cold. Is this normal? Someone told me the Transmission Fluid Temperature sensor does not allow overdrive when the transmission fluid is too cold. Why?
EASY!. 2 sensors u wanna chk out. The coolant and trans temp sensors.1 for power train computer and 1 for transmission computer. The reason behind this strategy is emission. If ur engine rev low at overdrive b4 warm up. It'll emission more hydrocarbon emission. Is the EPA man. But typical toyota if everything working normal. It should take about a few minute at ambient temp above 40 deg F to kicks in O/D. Unless ur temp sensors are outta range. Which is the job for ur mechanic to find out.
Good luck man
June, 10, 2007 AT 6:09 PM
I will try the coolant temperature sensor. It prevents overdive and lock-up under predetermined temperature 122deg-162deg
The computer monitors coolant temperature and sends the signal to the OD1 ECT ECU. The ECU will provide OD and Lock-up when the temperature has reach its calibration point.
Could be the throttle position and vehicle speed sensors, these sensors controls throttle and governor pressure.