Bad weather - 4wd operation

[TrkyMfns]

It seems probable that this may be a difference between the 2010-13 and the 2014+. I was messing around in some mud in 2WD and the traction control was lighting up like crazy. Once I put it into 4Hi, nothing. Now I didn't get it sideways or anything, but maybe it is less sensitive in 4Hi. Actually, I remember when playing in the snow in 4Hi in Michigan, I punched the gas and it slid a bit and I recall the traction control kicking in. I'd say punch it in 4Hi and see what happens.

 

[derekp]

Thanks guys. I'm going to hit the dirt road again for testing today. Until then:
I've yet to see the green A-TRAC light. Also 4-lo light blinks and beeps for me.

When I noticed the lack of VSC in 4H, I was meeting someone at the local church parking lot to give them a ride home due to weather. The ice had already hit so I started a 4wd donut in the abandoned parking lot and all wheels slide and spun easily. The only thing I can think of is that the asphalt was so slick that it fooled the computer, but that can't be correct and I know it. Also, on the way to her house we encountered a hill with a nice grade and just over half way up all wheels started to slip and spin. The truck began to rotate counter-clockwise just a bit until we hit some rough patches of asphalt and gained better grip. Once the passenger 's side front wheel grabbed grip, the truck corrected and we continued up the hill.
Not once did VSC or TRAC (not A-TRAC) kick in. I'll try a full ECU reboot this evening (I hate to have to reset my radio, LOL).

Thanks again for the in-depth investigation. It's amazing how this small issue is so frustrating.

 

[BLACK-FL4RUNNER]

Thanks guys. I'm going to hit the dirt road again for testing today. Until then:
I've yet to see the green A-TRAC light. Also 4-lo light blinks and beeps for me.

Problem solved!

If the 4lo blinks and beeps, it's not in 4lo. Atrac won't come on until it's in 4lo.

Please be sure to follow the proper procedure for shifting into 4lo.

 

[Whiplash Willy]

If the 4Lo light is flashing and beeping, that means it isn't in 4Lo. It means you have selected 4Lo, but it isn't/can't transition into 4Lo. When it is solid it is in 4Lo. If you aren't actually in 4Lo, you won't be able to turn on ATRAC.

Once you are in 4Hi (Solid Green Icon), come to a complete stop, shift into N, then select 4Lo. Once 4Lo goes Solid, press and hold ATRAC for several seconds, until the light turns on.

 

[derekp]

How long should you sit still in N? I sat for over 1 minute. I followed the instructions for Type B on Page 136 but have the blinking issue. (I really miss the 4wd lever from my 2001 Tacoma, and the 2012 4Runner.)
I wonder if I need to do the ECU reboot that rigtec suggested.

 

[BLACK-FL4RUNNER]

If you are stopped and in Neutral, it only takes 5 seconds or so for the light to stay lit. Then shift back into drive.
If it isn't going into 4lo, it sounds like you have an actuator or sensor issue.

How often do you put it into 4wd? Every month like the manual suggests?

 

[BLACK-FL4RUNNER]

Also, are you sure it's going into 4hi?
That would be the first step to help narrow your problem down...

 

[jwkilgore]

This sounds like problem with shifting the gears in the transfer case. For whatever reason it isn't shifting for you (for what it's worth, the manual lever in the 2012 worked the same way... all that lever did was flip a switch and the truck shifted the gears electronically. EDIT AGAIN: [MENTION=105875]96r50[/MENTION] is correct and I was wrong... it is a manual shift lever).

OR, you are shifting into 4Lo but a sensor is failing to tell the computer about the shift so it thinks you're still in 4Hi.

It's possible someone here may know a home remedy, but to me it sounds like you're in for a trip to the dealer (or other knowledgeable Toyota mechanic).

Quick check... go to 4High, manually set the shifter to a specific gear, then drive on a level road at a specific RPM. Write down your speed. Next shift into 4Lo and do the same thing. If you're moving the same speed in the same gear at the same RPM you never went into 4Lo and it's the shift actuator. If you are moving much slower in the same gear at the same RPM then you did successfully make the shift and there is a bad sensor.

As for A-TRAC, I know of one fool-proof way to check. Drive diagonally through a ditch or rut that's deep enough for two diagonal wheels to go off the ground. You can also do this by diagonally approaching a steep bank and trying to climb it with one front tire. Anything that puts all the weight on two diagonal tires. If the two wheels in the air start spinning and you get stuck, A-TRAC isn't working.

EDIT: If you try the last paragraph, make sure you can either back out of the situation or have a buddy along to pull you out if A-TRAC isn't working. Don't get stuck and blame some random guy on the internet.

 

[Phaedrus]

How long should you sit still in N? I sat for over 1 minute. I followed the instructions for Type B on Page 136 but have the blinking issue. (I really miss the 4wd lever from my 2001 Tacoma, and the 2012 4Runner.)
I wonder if I need to do the ECU reboot that rigtec suggested.

Just to clarify, we mean shift the transmission into N, not the transfer case. Once the transmission is in N, then the transfer case can be shifted into 4LO

 

[96r50]

(for what it's worth, the manual lever in the 2012 worked the same way... all that lever did was flip a switch and the truck shifted the gears electronically).

Actually, the lever is directly connected to the transfer case and does mechanically shift the truck into 4H and 4L. That's why it moves around and vibrates as you accelerate and brake. The ADD still has to run in order to connect the front axle together so engaging 4WD isn't a completely mechanical process but the manual shift lever isn't just a fancy switch.

 

[BLACK-FL4RUNNER]

The OP has the knob style switch, not a lever.

 

[4Rager]

As for A-TRAC, I know of one fool-proof way to check. Drive diagonally through a ditch or rut that's deep enough for two diagonal wheels to go off the ground. You can also do this by diagonally approaching a steep bank and trying to climb it with one front tire. Anything that puts all the weight on two diagonal tires. If the two wheels in the air start spinning and you get stuck, A-TRAC isn't working.

It also makes quite a racket, so you would hear it working as well, not to mentioned feel it.

 

[derekp]

I want to say thanks to all yall who helped me figure this out. Here is what I've done so far:

Last night, the issue of fuses was posted so I went to check. The under hood fuse box had a block of three fuses, all together, which covered the ABS/VSC and AIR PMP. I couldn't get the fuses out but they did move just a bit. Not sure if they need a particular removal tool. Anyway, after messing with those, I tried to cycle through 4H and 4L. 4H worked but not 4L.
This morning I walked out to run an errand and tried cycling everything again. 4H worked fine with a loud thud, the 4L worked with what sounded like a midget standing under the truck swinging a sledgehammer! One LOUD thud in 4L and one LOUD out of 4L. A decent thud in / out of 4H. Honestly, it startled me a bit. Anyway, while in 4L I pressed A-TRAC....woo hoo! The A-TRAC light came on (it does NOT come on during start up which I find odd).

I tested everything while out and about running my errand. VSC worked as usual in 2wd, still nothing in 4wd. As someone stated, while in 4L (with a loud thud) the TRAC light and VSC light came on. Thankfully that is working. As for A-TRAC, wow! I'm digging that. Once all that was activated, it lunged forward when I let off the brake. I suppose that is because the RPMs were up due to the cold.

The only things changed were:
1. Adjusting the fuses. That shouldn't have done anything, but there could have been a bad contact. If that were the case, wouldn't that have affected the ABS?

2. I haven't used 4L as much as 4H. I've owned 4wd trucks for years and know to run them for 10 or so miles a month and have done that with this one. Could the 4L solenoid have been stuck from lack of use? Is it completely different than the 4H solenoid? I didn't know if it was a two way/two stage actuator.

Again, thanks to those who were helping me walk through this. I might still do a full ECU reboot tonight to see if it corrects the 4wd VSC issue (and maybe relearns driving technique and environmental issues from our move).

 

[BLACK-FL4RUNNER]

Just try going 2hi 4hi 4lo a couple times when you have a chance. Something might of just needed to be "freed" up. lol

They will bang pretty loud if you go in/out 4wd on pavement, it binds the drivetrain a little and pops when cycled.

 

[ScoMey]

Just try going 2hi 4hi 4lo a couple times when you have a chance. Something might of just needed to be "freed" up. lol

They will bang pretty loud if you go in/out 4wd on pavement, it binds the drivetrain a little and pops when cycled.

Just an observation as I was reading through this...

be sure you have your foot on the brake when you are shifting to 4Low if you have the 'knob control'. Although I have a Limited, if I put the transmission in neutral, and turn the knob to 4L... I'm almost positive it won't shift until I also put my foot on the brake. The step by step in the '14 OM clearly states this for the part-time system too.

We now return to your previously scheduled programming...

 

[ScoMey]

Just an observation as I was reading through this...

be sure you have your foot on the brake when you are shifting to 4Low if you have the 'knob control'. Although I have a Limited, if I put the transmission in neutral, and turn the knob to 4L... I'm almost positive it won't shift until I also put my foot on the brake. The step by step in the '14 OM clearly states this for the part-time system too.

We now return to your previously scheduled programming...

Never mind. I was wrong. Engaging 4LO with the dial works even without the brake pedal applied. :redbrick: