My temperature sensor in my ml350 needs to be replaced. Could this cause trouble shifting to first gear. outside temperature is about freezing.

Here are some possible causes and steps to consider:

Check the transmission fluid level and condition. Shifting issues might be caused by low or filthy transmission fluid. Check that the transmission fluid is at the proper level and seems clean and red. If it is low or polluted, a fluid change and filter replacement may be required.

Transmission Solenoids: Modern automatic transmissions employ solenoids to manage gear shifting. A faulty solenoid might cause the transmission to stay in one gear. If needed, a professional can diagnose and replace malfunctioning solenoids.

Transmission Control Module (TCM): The TCM is in charge of controlling the operation of the transmission. It can cause shifting problems if it malfunctions or receives inaccurate sensor data. Check the TCM for fault codes and functionality.

Wiring and Electrical Issues: Examine the transmission's wiring and electrical connections, especially those to the TCM and sensors. Damaged wires, faulty couplings, or electrical issues can all disrupt transmission operation.
Shifting problems can also be caused by internal mechanical faults within the transmission, such as worn clutches, damaged gears, or a malfunctioning valve body. These problems can be diagnosed and repaired by a competent transmission mechanic.

Transmission Fluid Pressure: Proper gear engagement is dependent on transmission fluid pressure. Shifting might be affected by a malfunction with the transmission pump or pressure regulator. A pressure test can aid in the diagnosis of these problems.

Examine your vehicle for Diagnostic Trouble Codes (DTCs): Even if the knock sensor problem has been rectified, there may be more DTCs associated with the transmission problem. Check for any stored trouble codes with a diagnostic scanner to gain more insight into the problem.

I hope this might be helpful.

you can check the transmission fluid if its ok and also the transmission pressure

Yes, this could be the shift solenoid. Was the transmission filter changed at the same time as the fluid? Dirt in the system can affect some of the transmission sensors tripping Trouble codes. I cannot be sure what the P1732 code is as some codes can be very vehicle specific but it appears to refer to the transmission or on of it's sensors.

P0733 - Gear 3 Incorrect Ratio.
P0734 - Gear 4 Incorrect Ratio.

HERE IS THE ANSWER.
P0725 - Nissan Type Powertrain - Transmission - ISO/SAE Controlled Description Engine speed (RPM) - incorrect voltage signal ECM to TCM
Cause Wiring, RPM sensor, TCM, ECM
P0720 - Nissan Type Powertrain - Transmission - ISO/SAE Controlled Description AT - vehicle speed sensor (VSS)
Cause Wiring, VSS, TCM
P0710 - Nissan Type Powertrain - Transmission - ISO/SAE Controlled Description Transmission fluid temperature sensor - excessively high or low voltage
Cause Wiring, temperature sensor, TCM, ECM
P0826 - Generic Type Powertrain - Transmission - ISO/SAE Controlled Description Up and Down Shift Switch Circuit

the dtcs of your car are so many, my best suggest is go to garage for repair. or if you would like to repair by yourself, you need to buy a diagnostic tool such as multidiag j2534

sensor plug with white band goes to the outside sensor, they will plug in wrong and cause the same sympyom

Hi there are so many temp sensors fitted in to the your car which sensor you mean?

Have the tranny fluid changed. may want to change the filter at the same time.

some transmissions have sensors to tell the computor when it is at operating temperature. sounds like it needs replacing. this sensor may be located in the transmission pan. and can be changed very eslily.

the sensor is located behind the front grill about in the middle of the bumper rate me if this was helpful thank you.

Check your air filter is not clogged, also veriy the air mass sensor.