Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.
The code 218 will normally be the thing that set the 714 and yes, that could very well be the sensor. You will want to be sure that the engine is not running hot and the trans fluid is full. The valve body would have to come out to replace the sensor though. It is part of the trans range sensor.TRANSMISSION TEMPERATURE SENSOR Description
The transmission temperature sensor (2) (Fig. 257) is located in the transmission range sensor (1) and communicates transmission sump temperature to the TCM. OPERATION
The transmission range sensor (TRS) has an integrated thermistor that the TCM uses to monitor the transmission's sump temperature. Since fluid temperature can affect transmission shift quality and convertor lock up, the TCM requires this information to determine which shift schedule to operate inch The TCM also monitors this temperature data so it can energize the vehicle cooling fan(s) when a transmission overheat condition exists. If the thermistor circuit fails, the TCM will revert to calculated oil temperature usage. CALCULATED TEMPERATURE
A failure in the temperature sensor or circuit will result in calculated temperature being substituted for actual temperature. Calculated temperature is a predicted fluid temperature which is calculated from a combination of inputs:
- Battery (ambient) temperature
- Engine coolant temperature
- In-gear run time since start-up
AUTOMATIC TRANSMISSION - 42RLE
TRANSMISSION RANGE SENSOR
- Remove valve body assembly from vehicle.
Remove the manual shaft seal (1) (Fig. 253).
- Remove manual shaft/TRS retaining screw (1) (Fig. 254).
- Slide TRS off of manual valve shaft.
- Install the TRS (2) to the manual shaft. Make sure TRS locating pin rests in manual valve bore slot.
- Install the TRS/manual shaft retaining screw (1) (Fig. 255) and torque to 5 Nm (45 inch lbs.) torque.
- Install the manual shaft seal (1) (Fig. 256).
- Install valve body to the transmission.