Fun Service Visit. Should I be concerned?

So I took my truck in for my 15k service on Thursday. Also had them in check on a 4wd flashing light issue. Long story short I came in with a Tacoma and left in a Camry. All jokes aside they still have my truck saying I DO NOT have any 4wd currently and have no idea what's going on. This was Thursday when I was there for 6 hours. I "test" drove a IS350 F-Sport for a few hours to pass the time. Last time I was in 4wd was December. I'm guessing its some sort of sensor? Apparently they still haven't figured it out. Should I be concerned?

Unrelated, Toyota did a great job on the new Camrys.

 

Nope. Let them fix it. This is not a common issue.

 

I don't know how the 4wd activates in these trucks but if it's vacuum activated a vacuum tube might have cracked

 

Nope, all electric.

 

Yeah they may be making me a deal on a new one haha

 

That's what I'm thinking it has to be. Come Monday hopefully I'll hear something.

 

It is an electric motor that moves the shift fork on the ADD system

 

This video explains it pretty well

 

Nice video, found it very interesting. With it being a uncommon problem I guess I should be patient. After 3 days its getting harder.

 

You want it fixed or fast?

Sometimes parts availability on a rare problem can take a while, especially with shipping to a dealership over a weekend.

 

I 'broke' the 4wd system a lot while working on the 2Wheel Low mod, and it is easy to do. The computer checks alot of data to make sure it all appears correct, and if it isnt consistent, then lock out 4wd mode changes and display an error. The system is definitely set up to lock out when something appears amiss, and err on the side of system protection (I assume).

We can help diagnose exactly what was wrong if you had the truck (and a copy of techstream helps alot), but you don't need to. I am sure the dealer will get it worked out, but it can take some time to run it down.

Just for your info, the 4wd transfer system on this truck is all electric, including the front ADD actuator and the main transfer case actuator. The ADD actuator is located on the front differential, and it engages a sleeve on the front driveshaft. The main transfer case actuator shifts from 2hi into 4hi, to drive the front drive shaft, then into 4Lo planetary gears to give low range.

The 4wd system on the 3rd gen can detect small transients or errors that wouldnt necessarily be any problem, and locks out the 4wd system, presumably to protect the system from damage.

The system signals get checked on every engine start, and during 4wd mode changes. In general, the lockout gets cleared after engine restart, if the issue is no longer there. (The error will be stored and readable in techstream even if the issue is no longer present.) If you have an error that shows up on every start, the truck is almost certainly finding an error during the startup check.

Just a brief overview of what these startup checks include and what is likely wrong on each actuator:
Check actuator motor resistance, including resistance to ground (to check for shorted wires). If there is any bad connection to the actuator motors, or a short, then the system is locked out.
Check actuator feedback position sensors, to ensure they are consistent, ie (if front ADD locked sensor is 'on', then the unlocked sensor had better be 'off'. Both 'on' is not a valid position, and if the computer finds this condition then insta-locked-out).
If motor resistance is OK, and position sensors are OK, then the actuators are driven to the correct position as requested by the dashboard control if required. If the position sensors do not respond to the movement requests as expected, lock out after a time period (seems about 30 secs).

That is just a quick overview, and we can get into the techstream data and schematics if required, but just give the dealership some time. They probably havent had to work on the 3rd gen system much yet, and won't be super familiar with troubleshooting it. If I have to bet, a simple wiring bad connection in a connector that has to be located, or less likely an issue inside the position sensors of one of the actuators.

 

that video... man they over-complicated this crap. What every happened to just having the hubs locked or unlocked? pretty simple, unlock the hubs and nothing up front spins. Complete disassociation from the rest of the drive line.

Now you have one side spinning even in 2x4, hopefully you don't break anything.

 

Did someone say electric problems? Rats anyone?

 

Great write up, thank you. I do know it takes time, just hope not too long. I enjoy having my truck on a as need basis, hopefully won't run into anything the next couple of days. Again thank you for taking the time to write this up, very helpful.

 

Yeah I took it in about 14,500. Didn't want to wait on 15k. Issue had been around for about a week. Once I get a report I'll keep everyone in the loop in case there are any useful questions I need to ask.

 

More detail please?

Which year, trim, etc.

What is it you find 'great'?

It's in my top 6 for a replacement vehicle for an 04 CUV I have, so I'd enjoy hearing your views.

 

They gave me a 2018 SE with the 4cyl. Leather

They gave the interior a major upgrade in the last couple of years. Seats are very comfy, angle and reach of controls are very driver friendly. Exterior is very sporty taking subtle body hints from Lexus. Especially in the front. If you told me I had to buy one I would get the XSE (V6) or the SE (4cy) edition if you want the gas mileage. The safety features for 18' are nice, especially if you have a family or a wife driving. The car I'm driving has lane departure, front sonar and a few other things I like. For me personally its an adjustment being in a car. Def worth a checking out.

 

Electronic. Those old vacuum activated hubs sucked.
Dadumdum.

 

Any update OP?

 

4wd system is fixed pretty simply. It only takes a couple hours and there’s no blinking lights ever again!!