Hi all, I'm trying to do a transmission fluid drain and fill on my 2020 NX300. I've got the new fluid into the tranny, and now I'm trying to bring the transmission fluid up to the proper temperature before setting the fluid level.

According to the service documentation, if you don't have a scan tool, you can put the car into transmission fluid temperature sensing mode by shorting OBDII pins 4 and 13 together. But my car's OBDII port doesn't have a pin in position 13--it's empty.

Has anyone else ever seen this? How am I to know that the fluid temperature is correct for setting the level?

Thanks!

 

Check YT's vids from The Car Care Nut. I recalled seeing him ( Toyota tech ) doing a drain & fill in a Toyota sealed unit. Believed he did not need a temp readout but had his helper run the engine and shift the tranny forward/backwards several cycles to warmup fluid and added small amounts till fluid flowed from o'flow tube. Sorry, can help with the OBDII port question.
I did the sealed unit on my '05 4R some years back, using a handheld IR thermometer ( $20. or less ) to read case temp. Very useful tool cos one can check cat performance with it as well. good luck

 

Are you sure you have a correct connector pin diagram? You can orient your pin positions by referring to the wire colors on the attached version. The connector on my NX is mounted upside-down.

 

Yes, I had already ordered an IR thermometer just in case I couldn't figure out the connector pin issue. Thanks for you help.

 

Yup, as shown on your diagram, I'm trying to short pins 4 (ground) and 13 (ECU). But in my NX300's connector, pin 13 is empty. But thanks for the drawing; tomorrow, I'll look at the connector from the rear and see if I can identify a purple wire.

 

On second thought, I was so curious I went out immediately and took this picture, which shows the OBDII connector from the backside:



As you can see in the illustration you provided, there should be a purple wire between the red and white wires. But in my connector that position is empty. WTF?

 

You are correct; I don't see a wire in Pin 9 either. Other pins and colors agree with the diagram (view is a mirror image of your photo).
Lexus must have made a change for model year 2020 to access the Engine/Transmission Controller VIA the CAN bus (pins 6 and 14) instead of a direct wire.

 

Indeed. So my question remains: How am I to put the car into transmission fluid temperature sensing mode?

 

Just spent some money and get a Toyota specific
scanner that can read the trans and other basic modules.

 

Techstream, advanced OBD scanner or handheld IR thermometer

 

Here are a few tips for you.

Park your vehicle on a level ground, mark a spot in the middle of the front and rear pumpers. Measure the distance from the ground to the marked spots on the pumpers and jot down the measurements on a piece of paper

Set the vehicle on a lift so that the vehicle is kept level when it is lifted up (make sure the tilt angle from the front to rear and side to side of the vehicle is within +/-1°≈ 1", side to side ≈ .5")
The fluid temperature should be between 40°C (104°F) to 45°C (113°F)
The acceptable margin of error when adding fluid is +/-20 g (0.7 oz.) or +/-25 cc (1.5 cu in.).
Pay extra attention when adding fluid because adding an excessive or insufficient amount of fluid may cause a malfunction in the automatic transaxle.