ATF Level Check - DLC Jumper Method Doesn’t Work - #13 Terminal Absent

My 2021 Tundra recently hit 40k miles, so I drained and refilled the transmission fluid. I’ve checked the level once before when I added an auxiliary cooler, and at that time I used the exact OBD2 adapter and process shown in this video: https://youtu.be/5DLkja6vXvc

I drained just under 4 quarts and intentionally refilled with 5 quarts. My goal was to deliberately overfill it in case any air had worked its way out of the system from the cooler install and the fluid level was slightly low.

While researching the proper procedure again, I ran into the same conflicting information I’ve seen before regarding the correct fluid temperature for checking the level. Most sources (including the video above) say the fluid should be between 99F and 111F. However, I’ve never found a definitive Toyota service procedure for my model year. The factory procedure that’s commonly shared on this forum is for a 2007 Tundra, which has always left some doubt about whether the temperature range and process truly apply to newer trucks.

To eliminate any uncertainty, I decided to try the DLC jumper method to put the truck into ATF fluid check mode, as described in another PDF procedure that’s commonly shared on this forum. According to those instructions, you jump pins #4 and #13 on the DLC.

Here’s the problem: My truck does not have a terminal in pin #13. The cavity is empty.

I then started looking for videos on the jumper method, but most people now seem to use a scan tool instead. I did find this video: https://youtu.be/VZYrgfMx_gI

What’s strange is that although the presenter says to jump pins #4 and #13, she actually appears to be jumping pins #5 and #12 in the video.

At that point, I wasn’t comfortable risking electrical damage by shorting the wrong pins, so I abandoned the jumper method entirely and went back to using my OBD2 adapter to monitor ATF temperature and complete the level check that way.

So my questions are:

What model years of Tundra does the DLC jumper method actually apply to?

If there is a valid jumper procedure for a 2021 Tundra, which pins should be used?

Does Toyota still support the jumper method on newer trucks, or is a scan tool now the only correct way?

Any clarification from someone who has confirmed this on a 2019–2021 Tundra would be greatly appreciated.

 

Just omit the jumper and perform the drive select lever sequence.

 

I found a video for a Tacoma that said that as well. I tried it several times and it didn’t work. I waited until the fluid was 95F, started the engine, shifted to neutral for 2sec then quickly shifted between neutral->drive->neutral->drive repeated for 10-15 seconds. No luck.

 

I took a few tries to get to work on my Tundra, but it did work. Same for ‘21 4Runner and ‘22 Highlander

See page 12 of the attached service instructions for the UA80 transmission

 

Thanks for the info. I’ll have to give it another try to see if I can get it to work. A couple questions for you, according to step 6-F it says to move the gear selector between P and D, leaving the selector in each position for 3sec, to circulate the fluid through the system. Can this step be skipped and you roll right into 6-G? When attempting it on my truck, I did not go from P-D slowly before cycling between D-N. I skipped that step for a few reasons:

1. I had already run it through all the gear positions several times to circulate the fluid, so additional circulation was not necessary.
2. The fluid was already so close to 99F I didn’t want to waste time on stuff that wasn’t required.
3. I didn’t think 6-F was part of the procedure to activate check mode, I thought it was just to check the fluid. Maybe it is? Maybe you have to slowly go from P->D->P, then quickly do the D->N->D->N etc sequence.

6-K says “According to the display on the GTS, perform the Active Test Activate the TC Terminal and set it to ‘OFF’.” What are they referring to here? Is this referencing a factory scan tool?

 

Sorry refer to page 14, item 7 (not using GTS).

Basically, start vehicle, P > D > P (3 sec intervals) … D>N>D(repeat 1-1.5 sec intervals for 12 seconds until “D” stays illuminated, then shift to P. Gear selection will be blank until in temp range then “D” will illuminate. “D” flashes when above range.

I would have sent the AB60 transmission procedure (effectively the same), but could not find the file on my drive.

 

They changed wiring quite a bit, especially around 2019/2020 timeframe. You would need a wiring diagram but most use OBD adapters or bi-dirctional scan tools.

 

If you didn’t get it figured out with the shifter method, I can pull up the repair manual to see if pins changed for 20/21

 

My 21 doesn't have the correct pins either. It's still possible to get the engine to idle down before the trans fluid temps rise too high.

 

I just confirmed the UA80 transmission procedure to put my ‘21 4Runner into transmission fluid check mode. No jumpers or scan tool required.

 

I'd be interested to know what year it changed and when the pin jump method stopped working.

It must have changed at some point because earlier years supposedly had a terminal at pin #13.

I had to wait for the fluid to cool before attempting the fluid level check because I exceeded the temp range while cycling through the gears. Since the truck wasn't ice cold it didn't idle very high. Hopefully it's close!!!

Thanks. I'm about to take my lunch break and try it out myself. I skipped the step where you go from Drive to Park and back to Drive prior to performing the D->N->D->N sequence so that must be required.

I hope monitoring the temperature got it close because I'm reading that putting it into ATF check mode also engages a specific RPM to ensure accurate fluid level. The engine wasn't ice cold when I did it so it wasn't idling high. I actually exceeded the temp when cycling the fluid initially because I went to S mode and slowly went through all the gears several times. I had to wait for the ATF to cool to 95F before attempting the fluid level check while monitoring the temperature.

 

Dude, you were right! I got it to work! Thanks so much for the help! I was even able to get it into ATF check mode without doing the P -> D -> P cycle first so I can confirm that step is not mandatory. It’s a good idea, but not mandatory if the fluid has already been cycled through the system. I must not have been cycling it between D -> N -> D -> N for long enough.

You can hear the engine idle drop significantly before the D light comes on solid, so I’m assuming it’s an important step to make sure the truck is actually in ATF level check mode. Otherwise, the readings could be off if the engine RPM isn’t correct.

I immediately drove over to my buddy’s house, put the truck on a lift, added a quart of ATF, and ran through the level check procedure to drain out the excess.

Thanks again for the help!

 

I created a process for later model Tundra owners to follow. I don't know if it exclusively applies to 2019-2021, it may go further back, but hopefully it will help others who run into this.

 

Nice write up. Only technical word of caution is the actual reference temperature may be different than what you state in your guide. It’s kind of a moot point because if you’re using the fluid check mode, the ECU is going to indicate the appropriate temperature range. This mainly would affect someone trying to correlate a published temperature using an IR thermometer, which really isn't a best practice anyway.

 

I know that 99-111F temp check window is accurate for trucks dating back to at least 2018. I'm not sure when Toyota transitioned from 115-133F (as called out in the Toyota TSB TC009-07) to 99-111F, or if there were any values in between though.

As far as using a temp gun, I think that's pretty stupid when the truck has a built in temp detection mode. The Car Care Nut on YouTube showed a 20-24deg difference in temperature between the actual pan temp and what was displayed on his IR temp gun.

 

Where can I find the repair manual?

 

If you want to pay for it, you can checkout ALLDATA, I have seen a physical Haynes repair manual on Amazon for $30, but I’m not sure how much detail it actually has

 

Yes, ALLDATA covers most vehicles. Haynes for other cars have been worth the toilet paper it’s written on.

I'm hoping there is some form of Factory Service Manual available. I have a Volvo and 2015 is the last year a desktop version of the manual is available and it has to run on Win 7 on VMware.

There is a lot of misinformation on forums in general including YouTube University.

 

Charm.li is a great site with the same info that alldata has, it’s free but only goes to about ‘13 for toyota but could go newer for other makes

I think you can get a personal alldata account but I’m pretty sure it’s still pricey

 

I bought a 30-day pass to Alldata personal for GM vehicle; it was pretty underwhelming compared to the professional level Alldata. Also, while you could print specs and procedures, you could not download a full manual; nor did you have access to the actual factory service manual. Don't get me wrong, the information was valid, but it wasn't packaged in a way to keep on file like an eBook or .pdf book format.

If I were working on now if my Toyotasm I would use the TIS web portal: https://techinfo.toyota.com/techInfoPortal/

 

If you could download it then they can’t charge you monthly for it

but you can save all the DTCs local on your computer and reference them since they include the diag tree

what was the personal level missing?

 

I was planning a bunch of work on a 2009 Saturn Outlook and the information was just limited.... an example was dead links to procedures for replacing specific HVAC components, like the correct procedure of replacing a blend door actuator was total BS. Just showed the general location, IIRC; actual procedure would require removal of a good portion of the dash (doing it by the book). It was really hit or miss on good information. This was my first time using Alldata Persona...was like $20 for a month. Was better than nothing, I suppose, but some basic internet sleuthing for info is just as effective if less convenient.

 

The 01 Highlander repair info sucks too, it’s not terrible but it’s not great, could just be that there isn’t much info on the platform, I don’t think alldata created the info themselves unless it’s reported, (especially since charm.li has the exact same info); thy must get it from the manufacturer or somewhere else

 

Give me something to look up for the Saturn

 

if you want to have fun, look up a timing chain replacement

I was specifically looking for HVAC info because I was going to eliminate the rear section of the HVAC system. Obviously, no actual procedure for that, but I was able to get the refrigerant and oil capacities by component. Component replacement was pretty general, though.

 

Huh I’ll look at both and send em here to see if it’s any different

 

I have no need for that info, just sharing my limited experience with ALLDATA’s personal/DIY product.

 

yeah but youll be able to tell me if the personal vs commercial info is any different, but I suspect it won't be