Pairing MTH Ready-to-Run locomotives with DCS remote

Is the TIU set to TIU#1?  Have you tried resetting the TIU and the remote?  Did you try plugging the remote into the TIU with the 4 conductor curly phone handset cord?  This will eliminate the RF link from the remote to the TIU and verify the operation.

All that's required to run an MTH DCS locomotive on a working DCS layout is to add an MTH locomotive to the remote and operate it.

1st, do what John suggests with the curly 4 pin cord.

Also, try taking any other equipment of the rails, and just have the one engine powered up you wish to run. If that works, add the other stuff one at a time until you come across something that wrecks the signal. Keep in mind that it can be multiple items, even lighted cars.

Once you get the engine to add, do a track signal test to ensure that you have good signal. You may have to break the loop of track in one spot to help it not double back on itself.

If you still have issues after both of those ideas, you may have to look at the DCS software loaded in both items. It should be upgraded to the newest 6.1 in both. Version 5.0, had troubles adding engines.

How are you powering the TIU? Fixed #1 or aux power? When you press the read button does it find the TIU?

If they worked with explore the engines are fine, and you need to resolve your TIU issue.  As Joe said, make sure you power tiu via fixed one.  Watch the Red LED.  It should light, then flash at least once.  How ever many times it flashes would be TIU address.  One should be good for your set up.  Then press read to make sure communicating with TIU.  At that point with one engine on track, add it.  See how that goes.  G

Thank you for your suggestions. I really appreciate the prompt and detailed responses. Apologies for my delayed response. I got a chance to check the layout only today.

I tried the suggested methods and here is what I found:

1. The TIU LED is not lit. I have track power on Fixed Voltage IN1 and it is passing through to the track since I am able to operate Lionel engines on the layout. However, I read in a separate thread that the Fixed 1 is designed to pass the power through even if the TIU itself is not getting power. So I am not sure whether the TIU is actually working.
2. I read that I could test the TIU by powering it via the auxiliary power but I don't have an appropriate source for that - I believe I need a power supply with a 21V output. The only power packs I have are the power supply for DCS Explorer and the power supply for the Lionel LEGACY base.
3. I also tried connecting the remote to the TIU with a handset cord but the remote was not able to find it. This is to be expected if the TIU is not getting power.

For additional context, I bought both these component used and they had pre-existing settings. I have reset the DCS Remote but I am not able to reset the TIU since I can't connect to it

What do you suggest I should do?

No, anything from 12-18V AC or DC can power that TIU. You likely have a suitable power supply around and just mistook the requirements. The TIU power input regulates the voltage to the required logic voltage internally, and that is a low 5V for most of the logic, so power above about 8-9V is just needed for headroom above the regulated voltage. I power mine from a 12V DC adapter. The power brick for the DCS explorer can power the TIU.

you should be able to connect to the tiu as long as aux input is powered up you should hit read button on remote and it should report back tiu found and give you tiu number 1. on power up if you are watching the led inside the tiu it should blink like GGG told you ounce if it is not blinking your tiu is not working, count how many blinks on powerup! you should also be able to power up fixed one input and the led should blink on power up, if you put power on fixed 2  you will have to connect inputs variable voltage 2  to fixed 2 for blinking led to function. both red to red n black to black leads! if you led does not flash and then stay on tiu needs repair! 

You can actually use the aux power input on the TIU with anything from around 12V AC or DC up to 22 volts.  I use old laptop power packs on several of them on our modular club layout.

If nothing is lighting in the TIU with power on FIXED #1, it may be an issue with the power jack.  I don't remember if they do a power transfer if you plug in, but trying aux power is certainly worth a shot.

I connected the DCS Explorer power supply (15V) to the TIU, but the LED did not light up. The remote did not recognize it either.

I opened up the TIU, but everything looks okay to me. I have attached an image below in case any of you can spot a problem.

I also checked the Fixed 1 Voltage fuse and it seemed intact (that is why it's missing in the image above). Here's an image of the fuse:

Any other suggestions? Do I just have to take it back?

Sounds dead, it'll need to be looked at.  Just connecting that P/S should have at least got you the status light blinking out the address.

Quick update on the TIU: I took it to Legacy Station (my local train store). They tested it and concluded it was indeed dead.

They will send it to MTH to be fixed. I will let you know once I get it back.

Thank you all for your help.

That is a bummer, Nikhil!  I'm glad you are near enough to Legacy Station who you can trust to verify and send out to MTH.