Lexington
Member
A-TRAC vs MTS and When To Use Them
For a lot of new first time 4runner owners, the 4Runner comes with a lot of new cool Off-Road function such as A-TRAC (Active Traction Control), Crawl Control and MTS (Multi Terrain Select). Initially using these features can be intimidating and confusing. The most difficult was trying figure under what circumstances should I use A-TRACS and MTS. So, I began doing some research. I started with the manual, then watched a lot of videos, asked many questions on this forum and even talked to the dealers, who were not much help. I was finally able to understand how each system worked but when to use A-TRACs or MTS still eluded me. To me they both performed basically the same function, but if that was the case why did Toyota made two similar functions? There must have been a reason. As much as I researched I couldn't find a satisfactory answer. However, a few months ago, I was finally able to talk to a Toyota engineer at HQ and he finally gave me the answer I was looking for.
But before we get to that, if you’re new to the 4Runner let go over the two functions for a better understanding.
A-TRAC – A-TRAC works essentially as a faux differential locker. As a wheel starts spinning freely because it has come off the ground or is in loose dirt, torque wants to take the path of least resistance and will shift power to the free spinning wheel, thus robbing the opposite wheel with contact to the ground of torque and traction. A-TRAC use the computer braking system to apply the breaks on the free spinning wheel or wheels. This forces power and torque to the opposing wheel which has contact with the ground to give it traction and get you out of a stuck situation.
MTS – Where A-TRAC uses the computer braking system to optimize traction, MTS primarily uses throttle control to do this but it will also engage A-TRAC if needed. Also in some off-road situations, wheel slipping can be helpful and MTS allows limited slipping depending on the terrain selected. This slipping is controlled primarily by throttle control but if slipping becomes excessive or the vehicle encounters a free spinning wheel then A-TRAC is engaged.
So when is it best to use A-TRAC or MTS? The engineer explained to me, A-TRAC is a bit more aggressive and Crawl Control is very aggressive compared to MTS. This is because both systems rely heavily on the braking system to optimize traction. Used for a long period of time can cause the brakes and the transmission to over heat and potentially cause damage. However, the system is supposed to disengage before it gets to this point. Because the MTS first choice is to used throttle control to regulate traction and A-TRAC as a back up it puts less stress on these systems and is better in avoiding over heating of the brakes and transmission. So according to this engineer your best to start off with the MTS but if more aggressive traction is needed switch to A-TRAC or Crawl Control. Also, MTS is better suited for longer drive time.
So here is the general guidelines I would use.
MTS
Best used for general off-roading and light and moderate hill climbing and descending.
Mud and Sand selection is the only function that can operate in 4H and 4L. All other selection can operate in 4L only.
A-TRAC
Best used for moderate and difficult hill climbing and descending and when trying to get unstuck from a stop position.
Crawl Control
Best used for difficult and steep hill climbing and descending or when stuck in deep sand, snow or mud. (Very effective in sand.)
I will update this as suggestions come in.
I hope this is helpful. If anyone has any questions of if I made any errors, please let me know.
If anyone wants to watch a video on how these two systems work this is the best one I have found.
Finally, The Only MTS Video You Need to Watch! Multi Terrain Select Explained. ATRAC Demo! - YouTube
For a lot of new first time 4runner owners, the 4Runner comes with a lot of new cool Off-Road function such as A-TRAC (Active Traction Control), Crawl Control and MTS (Multi Terrain Select). Initially using these features can be intimidating and confusing. The most difficult was trying figure under what circumstances should I use A-TRACS and MTS. So, I began doing some research. I started with the manual, then watched a lot of videos, asked many questions on this forum and even talked to the dealers, who were not much help. I was finally able to understand how each system worked but when to use A-TRACs or MTS still eluded me. To me they both performed basically the same function, but if that was the case why did Toyota made two similar functions? There must have been a reason. As much as I researched I couldn't find a satisfactory answer. However, a few months ago, I was finally able to talk to a Toyota engineer at HQ and he finally gave me the answer I was looking for.
But before we get to that, if you’re new to the 4Runner let go over the two functions for a better understanding.
A-TRAC – A-TRAC works essentially as a faux differential locker. As a wheel starts spinning freely because it has come off the ground or is in loose dirt, torque wants to take the path of least resistance and will shift power to the free spinning wheel, thus robbing the opposite wheel with contact to the ground of torque and traction. A-TRAC use the computer braking system to apply the breaks on the free spinning wheel or wheels. This forces power and torque to the opposing wheel which has contact with the ground to give it traction and get you out of a stuck situation.
MTS – Where A-TRAC uses the computer braking system to optimize traction, MTS primarily uses throttle control to do this but it will also engage A-TRAC if needed. Also in some off-road situations, wheel slipping can be helpful and MTS allows limited slipping depending on the terrain selected. This slipping is controlled primarily by throttle control but if slipping becomes excessive or the vehicle encounters a free spinning wheel then A-TRAC is engaged.
So when is it best to use A-TRAC or MTS? The engineer explained to me, A-TRAC is a bit more aggressive and Crawl Control is very aggressive compared to MTS. This is because both systems rely heavily on the braking system to optimize traction. Used for a long period of time can cause the brakes and the transmission to over heat and potentially cause damage. However, the system is supposed to disengage before it gets to this point. Because the MTS first choice is to used throttle control to regulate traction and A-TRAC as a back up it puts less stress on these systems and is better in avoiding over heating of the brakes and transmission. So according to this engineer your best to start off with the MTS but if more aggressive traction is needed switch to A-TRAC or Crawl Control. Also, MTS is better suited for longer drive time.
So here is the general guidelines I would use.
MTS
Best used for general off-roading and light and moderate hill climbing and descending.
Mud and Sand selection is the only function that can operate in 4H and 4L. All other selection can operate in 4L only.
A-TRAC
Best used for moderate and difficult hill climbing and descending and when trying to get unstuck from a stop position.
Crawl Control
Best used for difficult and steep hill climbing and descending or when stuck in deep sand, snow or mud. (Very effective in sand.)
I will update this as suggestions come in.
I hope this is helpful. If anyone has any questions of if I made any errors, please let me know.
If anyone wants to watch a video on how these two systems work this is the best one I have found.
Finally, The Only MTS Video You Need to Watch! Multi Terrain Select Explained. ATRAC Demo! - YouTube
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