Discussion: how to make 4wd more reliable in the 5th gen

[5ontheFloor]

I believe [MENTION=106176]wfo9[/MENTION] mentioned a friend of his with a 5th gen made him realize this can become an issue but did not go into detail about actual incident. Great thread btw

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[changingtime]

The center diff in the limited is functionally no different from the front or rear diffs when it's not locked. It MUST allow for slip to account for the differing arcs the front and rear wheels take though a corner.

I'll state that I have not personally experienced the issue described here. However, going from H4F to H4L is exactly the same (functionally, not in implementation) as engaging 4WD on non-limited models. I'd expect Toyota would "protect" them in the same way.


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T Hanks...I specifically purchased the limited for the available awd feature understanding 4h/4L to be the same as non limited. I travel extensively and believe that putting a 4wd locked isn't a great idea due to drive line binding...on road that is.


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[wfo9]

Can anyone on here actually confirm that any code actually disables 4wd?

WHAT CODE? WHAT SENSOR? WHAT DID I MISS?

I do know that a code created by a wheel speed sensor can mess with anti lock brakes, downhill assist and traction control - BUT, until somebody shows me what code thrown by some sensor will actually disable the mechanical four wheel drive system - I don't believe it.

PRETTY MUCH ALL CODES All SENSORS...

You must not have done any reading... The entire point of the thread is the fact that any trouble code...Pretty much no matter what it is will disable the ability to go into 4wd. If you are already in 4wd things should keep working to an extent... but this still needs to be tested to find out exactly what does and does not work.

If you don't believe me... Go take off your gas cap. Drive a few times until the dash lights up like a Christmas tree.. Now, try to engage 4wd... even if you have a mechanical transfer case t4r, it won't enage. The reason is the ADD must also be electronically actuated by the ECU. Toyota decided to disable all transitions to 4wd/center lock... when any trouble codes activate. Yes it is horrible for those that off-road .. thus the reason for the discussion to come up with mitigation strategies.

The best most logical strategy discovered at this point... Is to carry a code reader/scanner and use it to clear codes so that 4wd can still be engaged. The next level (if that wont work) and the problem is a 4wd switch in the tcase... will be some strategy to manually slide the ADD collar over. This has not been determined yet, but I should have some time in about 2 weeks to figure it out.

What made me realize this mess was an experience of a friend on a remote trip through Utah and AZ... He had a cat efficiency code thrown and could not engage 4wd.. He got into cell coverage for a bit and texted me for help. Further research revealed that Toyota disables 4wd for just about any trouble code, including the gas cap EVAP... which is extremely common.

Full disclosure. I have never had my 4wd system disable... This information is all based on data I have gotten from others, but I don't know why they would lie about it. All the info seems to be correct and corroborated by others. I would go test it now, but I'm in the middle of fixing my other truck and getting it ready for Lonestar Toyota jamboree next week.

I I get a cel on it.. 4wd still works like it should. Those were the days...:sobbing:

 

[Bilbo]

The center diff in the limited is functionally no different from the front or rear diffs when it's not locked. It MUST allow for slip to account for the differing arcs the front and rear wheels take though a corner.

I'll state that I have not personally experienced the issue described here. However, going from H4F to H4L is exactly the same (functionally, not in implementation) as engaging 4WD on non-limited models. I'd expect Toyota would "protect" them in the same way.

[MENTION=809]fattire[/MENTION] Are you sure? The Torsen center differential is a completely mechanical limited slip differential. The axles rely on electronically-controlled LSD systems.

Now, what happens if your O2 sensors go kablooey, I have no idea. But the center differential does not lose its LSD capabilities.

 

[wfo9]

[MENTION=809]fattire[/MENTION] Are you sure? The Torsen center differential is a completely mechanical limited slip differential. The axles rely on electronically-controlled LSD systems.

Now, what happens if your O2 sensors go kablooey, I have no idea. But the center differential does not lose its LSD capabilities.

He said you would not be able to lock the center differential... and be limited (no pun intended) to 3 open differentials. Not sure how bad that is in real off-road conditions... Much better than 2wd, but not as good as a locked center differential.

But you are right.. the center is technically not fully open. it is a form of limited slip. (dang the name Limited really makes sense LOL)

With the limiteds you don't have ADD to deal with, but the transfer case is electronically actuated. So you can't lock the center or go to 4L...

 

[fattire]

[MENTION=809]fattire[/MENTION] Are you sure? The Torsen center differential is a completely mechanical limited slip differential. The axles rely on electronically-controlled LSD systems.



Now, what happens if your O2 sensors go kablooey, I have no idea. But the center differential does not lose its LSD capabilities.

[MENTION=106176]wfo9[/MENTION] beat me to it. See his post immediately above.

I do apologize for a lack of clarity in my post though [MENTION=101428]Bilbo[/MENTION]. Working from my phone while out and about with the kids all day.


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[1engineer]

So two things then:
1. Somebody with a reader that can clear codes needs to throw a few codes and see what's up.
2. How common is this? I will do a poll. I like polls...

 

[4RunnerAquasport]

He said you would not be able to lock the center differential... and be limited (no pun intended) to 3 open differentials. Not sure how bad that is in real off-road conditions... Much better than 2wd, but not as good as a locked center differential.

But you are right.. the center is technically not fully open. it is a form of limited slip. (dang the name Limited really makes sense LOL)

With the limiteds you don't have ADD to deal with, but the transfer case is electronically actuated. So you can't lock the center or go to 4L...

In certain terrain you might be better off with 2wd. With the center differential unlocked, my limited does OK in moderately deep sand with momentum of course. Add any articulation and traction loss, thats when the alarms go off and the truck does not respond well. A skilled driver and spotter with 2wd might have better luck at that point.

 

[Ron4RNevada]

I don' believe it - Of the 100,000 people on this forum; someone would have brought this up.

Think about it: People on TR4.ORG complain about noisy seat belts, noisy suspension parts, rubbing oversized tires, leds that don't wire up right, scrapes on skid plates, everything imaginable - really stupid complaints about things -

SOMEONE AT SOMETIME WOULD HAVE SURELY COMPLAINED AT LEAST ONCE THAT THEIR 4WD SYSTEM FAILED TO OPERATE PROPERLY WHILE THEY HAD A CEL.

Heck my wife's Camry has for years gotten CELs for fuel vapor errors - I used to go buy new gas caps a lot - For the past six months we have decided to just leave the damned light ON. EVERYTHING on her car works perfectly with the CEL ON.

I think this thread is much ado about nothing. Do the poll Greg!

 

[blanchard7684]

...which goes to show how little you know about complete systems. When certain components fail on say, an aircraft, there is redundancy built in. In addition to redundancy, there are other systems that shut down to keep from messing up other components. Do you want to pay $100K for a properly designed bulletproof 4Runner? Nobody else does either, which is why they are not built like aircraft.

Loss of 4wd over something trivial like an 02 sensor, etc, could be a serious problem for an owner in many situations with this type of vehicle.

It doesn't take $100k to think that one through in systems thinking and FMEA.

 

[Engineer]

For those contributing - good discussion. For those who think this is an actual concern......how do you get through a day in life without loosing your mind worried about much more prevalent hazards/concerns? One case, two cases.......a dozen cases does not make this a reliability problem. Not directed at OP, I think the intent of the post was a discussion with a couple data points provided.

If you have the 4runner somewhere that you truly need 4x4 and can not walk out or contact someone then in all likely hood you have radios, GPS Beacons, Shovels, Traction mats, Winch, Rope and a stubborn self reliance that says " Like hell if I can't get myself out of this" - I don't think having a running 4runner that only has 2wd is going to hold you back.

Do I like that this could happen, no but I am not going to argue with the internet about what Toyota coulda/shoulda done. If you don't like it - Go by a Jeep and tell me if you feel better in that then the Toyota in these imaginary scenarios

Moving on the the "problem"

Option 1A: Code reader to clear codes - may not help in all situations if the code comes back on start up

Option 1B: [MENTION=65614]Antman[/MENTION] has the right idea, power/ground the ADD to get it to engage - not sure what else there is to discuss. This seems the most logical , realistic solution. Granted this may be easier said then done

Option 2: AWD / FJ Cruiser (manual) Transfer Case swap - Deletes ADD, and Transfer case electronic accusation - you would have complete control, the electronic nannies may not function

Option 3: Go with a friend in another Toyota (last but most preferable)

:gun5::frusty::boxing:

 

[wfo9]

For those contributing - good discussion. For those who think this is an actual concern......how do you get through a day in life without loosing your mind worried about much more prevalent hazards/concerns? One case, two cases.......a dozen cases does not make this a reliability problem. Not directed at OP, I think the intent of the post was a discussion with a couple data points provided.

If you have the 4runner somewhere that you truly need 4x4 and can not walk out or contact someone then in all likely hood you have radios, GPS Beacons, Shovels, Traction mats, Winch, Rope and a stubborn self reliance that says " Like hell if I can't get myself out of this" - I don't think having a running 4runner that only has 2wd is going to hold you back.

Do I like that this could happen, no but I am not going to argue with the internet about what Toyota coulda/shoulda done. If you don't like it - Go by a Jeep and tell me if you feel better in that then the Toyota in these imaginary scenarios

Moving on the the "problem"

Option 1A: Code reader to clear codes - may not help in all situations if the code comes back on start up

Option 1B: [MENTION=65614]Antman[/MENTION] has the right idea, power/ground the ADD to get it to engage - not sure what else there is to discuss. This seems the most logical , realistic solution. Granted this may be easier said then done

Option 2: AWD / FJ Cruiser (manual) Transfer Case swap - Deletes ADD, and Transfer case electronic accusation - you would have complete control, the electronic nannies may not function

Option 3: Go with a friend in another Toyota (last but most preferable)

:gun5::frusty::boxing:

Sure, it's not the end of the world...and really not big deal when daily driving...

But picture this. You take 2 weeks off work (it's your one vacation per year). You plan your trip for 6+ months with all your routes (lots 4wd...). Pile in and head out 1500 miles (btw this subject was never presented to you, so you have no clue or equipment to deal with it...)... The point of the trip is to explore remote areas.... 2nd day in... CEL for cat efficiency. Trip is a bust unless you can get to a dealer (5 hours away) and pull your pants down and close your eyes... Picture this scenario on that ridiculous unrealistic show expedition overland that Toyota supports. I think that would leave you a bit frustrated with Toyota diagnostic engineers... and I know they would edit it out.

And right, the point is not to ***** about it, but to raise awareness and discuss mitigation strategies.

But any sane person would have to admit that it is a poor design choice and not that far fetched of a scenario. I would not call it common at all.. but as time goes on it will actually be something that happens to plenty of 5th gens.

 

[5ontheFloor]

I don' believe it - Of the 100,000 people on this forum; someone would have brought this up.

Think about it: People on TR4.ORG complain about noisy seat belts, noisy suspension parts, rubbing oversized tires, leds that don't wire up right, scrapes on skid plates, everything imaginable - really stupid complaints about things -

SOMEONE AT SOMETIME WOULD HAVE SURELY COMPLAINED AT LEAST ONCE THAT THEIR 4WD SYSTEM FAILED TO OPERATE PROPERLY WHILE THEY HAD A CEL.

Heck my wife's Camry has for years gotten CELs for fuel vapor errors - I used to go buy new gas caps a lot - For the past six months we have decided to just leave the damned light ON. EVERYTHING on her car works perfectly with the CEL ON.

I think this thread is much ado about nothing. Do the poll Greg!

Heh heh out of 100k members how many actually wheel remotely as [MENTION=106176]wfo9[/MENTION] is surmising in this scenario. Or how many actually use their 4wd often enough to have get a CEL to go off while in 4Lo? If i had a code reader id go outside and test it myself just to know. Im one of those guys that this kind of weird one in a million type of things would happen to.

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[1engineer]

Sure, it's not the end of the world...and really not big deal when daily driving...

But picture this. You take 2 weeks off work (it's your one vacation per year). You plan your trip for 6+ months with all your routes (lots 4wd...). Pile in and head out 1500 miles (btw this subject was never presented to you, so you have no clue or equipment to deal with it...)... The point of the trip is to explore remote areas.... 2nd day in... CEL for cat efficiency. Trip is a bust unless you can get to a dealer (5 hours away) and pull your pants down and close your eyes... Picture this scenario on that ridiculous unrealistic show expedition overland that Toyota supports. I think that would leave you a bit frustrated with Toyota diagnostic engineers... and I know they would edit it out.

And right, the point is not to ***** about it, but to raise awareness and discuss mitigation strategies.

But any sane person would have to admit that it is a poor design choice and not that far fetched of a scenario. I would not call it common at all.. but as time goes on it will actually be something that happens to plenty of 5th gens.

I agree, this is a good subject to talk about and it sounds like a code reader is a handy tool to have in your box. But by your logic presented above and using your example, and knowing this is a rare occurrence, ANYTHING that breaks is going to make your trip miserable. A battery or alternator, your ECU, lost key, etc and if these things fail it is worse than only going into 4WD. We carry spare parts based on statistics. Nobody carries everything. My point is sure, it could happen. Is it more likely than a major electrical component like a battery, alternator or ECU? I would take 2WD versus a 4600 lb boat anchor.
Bottom line: Buy a code reader and learn how to use one.

 

[Antman]

I agree, this is a good subject to talk about and it sounds like a code reader is a handy tool to have in your box. But by your logic presented above and using your example, and knowing this is a rare occurrence, ANYTHING that breaks is going to make your trip miserable. A battery or alternator, your ECU, lost key, etc and if these things fail it is worse than only going into 4WD. We carry spare parts based on statistics. Nobody carries everything. My point is sure, it could happen. Is it more likely than a major electrical component like a battery, alternator or ECU? I would take 2WD versus a 4600 lb boat anchor.
Bottom line: Buy a code reader and learn how to use one.

Well... you could always tow a brand new 4Runner on a trailer on your trips. One breaks, swap 'em. Talk about carrying everything.

 

[Jhalko]

Well... you could always tow a brand new 4Runner on a trailer on your trips. One breaks, swap 'em. Talk about carrying everything.

Better just to not take it off-road to begin with! :hippie:

 

[wfo9]

I don' believe it - Of the 100,000 people on this forum; someone would have brought this up.

Think about it: People on TR4.ORG complain about noisy seat belts, noisy suspension parts, rubbing oversized tires, leds that don't wire up right, scrapes on skid plates, everything imaginable - really stupid complaints about things -

SOMEONE AT SOMETIME WOULD HAVE SURELY COMPLAINED AT LEAST ONCE THAT THEIR 4WD SYSTEM FAILED TO OPERATE PROPERLY WHILE THEY HAD A CEL.

Heck my wife's Camry has for years gotten CELs for fuel vapor errors - I used to go buy new gas caps a lot - For the past six months we have decided to just leave the damned light ON. EVERYTHING on her car works perfectly with the CEL ON.

I think this thread is much ado about nothing. Do the poll Greg!

People have complained... It's a real thing... What proof do you need. Go try it! They are just not old enough yet for it to be common yet. Just like you said about your wife's Camry. Intermittent MIL will be very common as they age and people who don't have a mechanism to clear codes will not be using 4wd. It's your choice to not carry one. I would!

 

[DeepSea]

I thought having a manual transfer case like in the TRAIL, TRD PRO, or FJC was a bulletproof 4WD system compared to the push button/turn dial system in their other models? My previous Tacoma's all had the dial and often I'd hear it forcing itself in/out of 4WD. Sometimes beeping, sometimes chinking

 

[007Tacoma]

My 2003 would have left me stranded on some trails in Colorado 3 years ago for O2 Sensor issues related to catalytic converters if I hadn't had my Scan Gauge II. I didn't get on here and complain about it, but I did get on here to find out what I could do about on day 1 (which wasn't on the trails).

The advantage I had was that I already knew the CEL/MIL was going to come on. When that would happen I had gotten to the point that I could reset it on the scan gauge without even looking. By the time it would happen on the trail, it was an easy fix. Frustrating? Yeah. Did it leave me stranded? Never.

...now if we want to ***** about something on the 4th Gens: Zero Point Calibration.:redbrick:

 

[flyrv9]

Someone asked earlier how to use a code reader. Mine (a cheapo from Pep Boys) came with a book as I'm pretty sure most do. The book also listed the codes and description.