I have a 2006 Hyundai Santa Fe and the ABS & TCM lights came on. I googled and found out the speed sensors could be the problem. I bought after market sensors one at a time and have replced them all. The lights went off as I finished the last one (front passenger side) but came right back on. I drove around for a long time and parked it for several weeks. Upon cranking it the TCM light also came on and it is in Limp mode. Could the ABS & TCM issues be causing the TCM (Limp Mode) issue?
This morning I did find out (on this Forum) that the brake switch could be bad or the speed sensor tone ring could be cracked and I will check this out starting with the front passenger side. Does the rear rings usually crack?
Thanks For Your Time and Assistance!!

 

Based on what you're describing, it sounds like the ABS and TCM lights might be linked to the speed sensor tone rings. Since you’ve already replaced the sensors, the next step is to check those tone rings closely, especially the front passenger side where the lights went off briefly. Look for any cracks or damage on the rings. A small crack can cause the ABS to misread the wheel speed, which can also mess with the transmission and put it in limp mode. Also, consider checking the brake light switch because a bad one can throw off signals to the ABS and TCM, causing the same lights and limp mode issue. It’s a relatively easy and cheap fix if that’s the problem. If those checks don't show anything, then take a look at the wiring and connectors for any damage or corrosion since that could also be the culprit. Make sure the connections are clean and tight. Good luck!

 

Thanks for the reply, Yernaz. I checked the passenger side first and the ring is cracked. After hours of searching I finally found the obselete OEM parts on eBay. I ordered two rings. I then checked the driver side and that ring is cracked as well. I have everything ready to replace these rings once they arrive. Hoping this will correct all the issues??!! If not, troubleshooting will continue! Thanks Once Again

 

You're on the right track by finding the cracked rings and ordering replacements. Cracked tone rings can definitely cause ABS and TCM issues, so replacing them should help resolve the problems you've been experiencing. Once you get the new rings installed, make sure to clear any fault codes if they’re still present, either by using an OBD-II scanner or disconnecting the battery for a few minutes to reset the system. After that, take the car for a test drive to see if the lights stay off and if it’s out of limp mode. If the issues persist, it might still be worth checking the brake light switch and wiring for any other faults, but replacing the cracked rings is a solid step in the right direction. Good luck, and I hope this solves the problem for you!

 

Thanks Once Again Yernaz,
After replacing both front tone rings I drove around my property. I still have the ABS, TSC and Engine lights on. I checked with the code reader and have PO700 & PO885. Maybe a bad Traction Control module among other things?
Trouble shooting continues!!
At least the tone rings purchase was not wasted money as they were broken!
More Updates as they come.

 

It’s great to hear you got the new tone rings installed, and it’s a good thing you replaced those cracked ones. Even though the lights are still on, replacing the broken rings was an important step in ruling out the cause of the problem. The codes you’re seeing, P0700 and P0885, are related to the transmission control system and the transmission relay, which could point to issues with the Transmission Control Module (TCM) or its wiring. A faulty TCM or a problem with the relay circuit could definitely keep the ABS, TSC, and engine lights on.

Since the tone rings are no longer an issue, it might be worth focusing on the TCM next. Checking the wiring and connectors to the TCM for corrosion or loose connections could help. Also, inspect the transmission control relay, which might be faulty or have a poor connection. If everything looks good but the problem persists, the TCM itself could be the culprit. Keep troubleshooting, and hopefully, you’ll pinpoint the issue soon. Good luck, and looking forward to more updates!

 

As with everything else on this project, find the correct location for mine is always hours of searching and researching. I've had the TCM or TCU out already after the dealership found the exact location for me. I've found a guaranteed used one but went with the ABS & TSC errors first.
And I would have checked the Transmission Control relay a long time ago if I could find it. Here's a picture of what's under the hood on mine. Under the steering whell are all fuses except for two of these relays that aren't even shown on the lay out cover??
Wish Me Luck!! I only mess with it from time to time.....it's nothing I have to get fixed in a rush!

 

Sounds like you’ve been through a lot with this project, and I get how finding the right parts and relays can be a real pain. From the pics, it seems like you’ve got a good understanding of what’s under the hood and steering wheel, but tracking down that Transmission Control Relay can definitely be tricky, especially when it’s not clearly marked or shown on the layout.
Since you’ve already dealt with the TCM/TCU and the ABS/TCS issues, checking the Transmission Control Relay makes total sense. But if it’s not labeled on the fuse box diagram, it might be hiding somewhere less obvious—maybe it’s integrated with another component or tucked away in a different spot.
Since you’re not in a rush, take your time tracing the wiring from the TCM/TCU to see if it leads to a relay that isn’t clearly marked. Sometimes these things are placed in sneaky spots or combined with other relays/fuses. If that doesn’t work, a detailed service manual for your specific model might have the info you need.
Good luck with everything, mate!