I will not quit! Dreaded 4hi/4lo/diff lock flashing lights. Work done but problem still exists

Tundras.com experts, I'm new to this forum but have been at Tundrasolutions.com for a decade. It was getting slow over there and PHM recommended that I give a few shouts on this platform.

Background: 2006 Sequoia SR5 4x4, 210K miles, never mudded, some towing, owned for 12 years, FLA car but first four years of its life was in NY. (frame inspected and determined to be in limits). Original trans, no oil burn, leather and paint are showing their age. Never any major problems. Wife jackknifed the "Beast" a couple of years ago while I was serving in Bahrain for a year. Truck drove away... cosmetic damage. We can't justify getting rid of her (not my wife, the truck!) and want to give her to my son in a few years.

The Problem: About six months ago, I was getting an intermittent flashing of all three lights... 4HI/4LO/Diff Lock. I would put it in 4HI or 4LO and the issue would go away after driving for a while. About two months ago, the lights stayed on and I was getting poor gas mileage. I flogged the darkest corners of the interweb, went to the University of YouTube, and after making a desperate decision, decided to replace the front diff actuator. $585 from my local Toyota dealer. It was a tight spot but I got it in. I used the black Toyota gasket sealer that I had left over from my valve cover gaskets. No leaks. Replaced the front diff oil at the same time.

What else have I done? Well, I verified that the goofy 20A fuse is good as were all of my other fuses. I then pulled up the "Inspect 2WD/4HI, 4LO and Differential Lock Switch Continuity" wiring diagram from page 2980/TR-42 on the 2005 Sequoia Repair Manual. I tested the continuity on the switches per the manual and did notice that I have two switches that are not operating according to spec. (Diff Lock HOLD on had continuity on a different pin which is bizarre and I had no continuity on the 2WD/4HI HOLD on test).

Something else that I noticed about a month ago is bothering me. When the issue first started, I could hear relays clicking behind the dash almost like a soft turn signal sort of sound. It would change in tempo when I tried to push the 2WD/4HI button. Again, for a while the issue would fix itself, but now the buttons don't make a sound and I do not hear any relay sounds at all. Maybe my switches are the issue, I don't know.

I put the Beast on jack stands yesterday to confirm that it indeed was in 4WD... Yup. It is stuck in 4WD. I tried disconnecting the front diff actuator plug while the power was killed. Then I put it in accessory mode and shifted into neutral. I spun the hell out of all wheels in both directions in an effort to synch up the actuator but it did not make a difference. I then plugged the front diff actuator plug and here I am.

Am I going down a rabbit hole on the instrument panel finish lower panel switches? Why am I no longer hearing those relay sounds that I used to? Before I continue to shoot the parts cannon at it, I am wondering if anyone else has had this exact issue and what was done to fix it. Replacing the trans case actuator sounds like a bigger job than the front diff actuator so I'm hesitant to jump straight to that. I'd like to thank N84434 and PHM in advance.

I plan on spending most of the day helping my 13 year old wrench on his 1981 Toyota pickup... talk about a labor of love...

 

Welcome Scud;
It's possible that the actuators are out of sync with each other and the ECU. Get All four wheels off the ground, set for 2 wheel drive Hi, what spins, and what is free?
1) Check the rear drive shaft to see if it spins the front drive shaft through the XFR case
2) Check the front drive shaft to see if it spins the front tires.
If everything is spinning like it's in 4 Hi, the system is not synced to the switch/ ECU.
Disconnect the battery, engage 4 Hi, connect battery, start truck and see where you are with step one again.
If you start the engine, and put it in drive while tires are off the ground, the diagnosis might be easier.

3) disengage 4Hi and see if the front stops spinning. If the front drive shaft still spins, but the tires don't, the XFR Case actuator is no doubt stuck.
You can try a little tappy-tap with a dead blow on the XFR case actuator to see if it wakes up.
4) report back with findings...

and give our regards to PHM. He is missed...

 

I wish that I had the manual floor shifter but I have the push-button selector switches. When I push them, they don't do anything. When I had it in the air and put it in drive or reverse, the front wheels were turning along with the rears which told me that I'm stuck in 4HI. I disconnected the front actuator plug and spun all wheels for quite some time in all directions to no avail. I did disconnect the battery overnight and this didn't help. :-(

We may have localized the issue to the switch/ECU. Is there a test that I can do to start troubleshooting on those? I did the conductivity test and indeed my switch did not behave as specified in the repair manual. My switch which is basically the front faceplate below the radio would have to be replaced. I don't think that I can replace the pin brackets and the circuit board independently. I may have to buy the whole instrument panel finish lower panel.

I'd like to revisit the recent absence of any clicking/relay sound/soleniod sound emanating from the dash. My switch used to activate the sound until the action was complete. Now I have total silence regardless of what I push on the switches. What was clicking when I pushed a 4wd button? Was it a relay or solenoid somewhere either in the dash or behind the passenger kick plate?

I'll try whacking on the XFR case actuator to see if that does anything. It's worth a shot. Thanks much for the advice!

 

Like, literally nothing? No solid or flashing lights on the button you press, no beeping? And nothing in the dash, no flashing green indicator?

When you mentioned clicking in the dash, 1st thing that came to mind is relays. I'd need to crack open the electrical wiring diagram (EWD) to see if there's a relay in-line, but I hate trying to read Toyota's EWDs. They're pretty illogical to me, I don't get how people decipher them.

You get everything else in the center dash, though? HVAC controls light up, clock is working, radio turns on? Just making sure there's not a connector on the back of the center dash controls that's off. We've had a number of newbies post on here asking why their new aftermarket radio wouldn't turn on after install, and it's because the radio draws power from one of those connections on the back of the dash.

 

ABS sensor???

 

Shifty... thanks for chiming in. The buttons do not light up, no sound. I used to get an instant action from the buttons such as that clicking sound from a relay somewhere doing its thing. The 4HI 4LO and Diff lights are constantly blinking in the instrument cluster. A couple of months ago, if I tried pushing the 4HI/4LO button in neutral it would quiet down and go away. I'm guessing that it was working intermittently at that time. Fast forward to two weeks ago when I replaced the front diff actuator with an OEM part and the lights have not changed.

Everything else in the dash lights up and works fine. Radio, HVAC, clock... all good. Factory JBL. I installed a SIRUS FM receiver 10 years ago but that has been disconnected for some time. I pulled the center dash panel off yesterday to test the pins. While I was in there, I looked at the circuit board housing the buttons to see if I could see something ridiculous like burns or discoloration. Nada. I replaced some crappy Chinese LED lights with new crappy Chinese LED lights which should last for a few years before they start making my dash panel look like a disco at night.

I'll try to see if the lights on the actual buttons do anything when I press them. That may be an interesting observation. I don't recall if the buttons gave off different lights or not.

 

Didn't mean to mislead you there. I'm aware there was no manual transfer case lever, like the Taco had. Disconnecting the actuator plug won't do anything, tbh. However, disconnecting the plug, removing the plastic cover from the actuator and manually moving the worm gear, to reposition the actuator WILL do something.

if you reposition the actuator manually, you may be able to get it to sync with the ecu/switch. I'd have to look it up, but after removing the plastic cover and noting the position of the gear, you can decipher what position the actuator is in, and where it should be in relation to the switch.

Hope that makes sense...

 

Ahhh.... I am also a random victim of the traction control/brake/abs lights all lighting up from time to time. I have seen in other threads where this could be related to the 4WD system. A few weeks ago, the three traction control/brake/abs lights came on when my 4HI/4LO/DIFF lights were on. I started to question what I did wrong in life to have six idiot lights going off on my dash at the same time. It was depressing. Usually when I restart the vehicle, the ABS/TRAC/BRAKE lights go away. They appear from time to time and go away for a while. If ABS sensors are a relatively easy and cheap fix, maybe that is worth exploring. Are these just electrical gizmos with plugs on both ends that plug into your hub assembly?

 

Jim... good point. I tried to remove the phillips head screws on my old actuator but they were locked up tighter than a clam with lockjaw. The brand new OEM one should be much easier to get open. I'm out of time this weekend and have several grizzly weeks of my pesky day job ahead of me, but I can see myself manually moving the worm gear to see what happens after I disconnect the front diff actuator plug. It may be a while before i can get to that but I'll try. I'm not giving up on the "Beast".... she has shuttled my family around for far too long.

 

I had one go bad on my 4Runner at the time and the all the lights you mention would light up, some would flash, and at first it was intermittent and would go away with a restart of the vehicle. Eventually it was on all time. Took it into the dealer and diagnosed it as an ABS sensor. Got replaced and all was good. I'm wondering if it would show up on a diagnostic tool of exactly what it is? Pondering this because it took the dealer no time to come back and tell me what it was.

 

To this point, @Scuddog I'm going to ask that annoying ass question: Did you check fuses, relays, and connections inside the engine bay fuse/relay box?

I'd expect ABS sensor to trigger a dash light, but ... it hasn't been the case with others here in the Gen1 group.

 

Wally... I have a scanner and no codes have popped up in years. I will run a scan again. If the dealer pinpointed it... it had to be a code, right? Do you know if you paid an obscene amount of money for the sensor?

 

Shifty, no worries! While I checked that goofy 20A fuse in the driver's knee panel area, I checked the rest of them. I also checked all of the blade fuses in the engine bay. Every compartment. I'm no relay expert, so I did not check the relays. The odd square shaped fuses all appeared to be intact. If you have tips on how to test/check a relay, I'm all ears!

The response on this forum is refreshing. Thanks to all of you for lending your 2 cents!!!

 

I'm not sure if a code pops up or if they found it using their factory diagnostic stuff? Sorry I can't be more help than that but this sounds similar to what happened to me. Their was another guy with a 2nd gen Tundra that had something similar and his ended up being something with his tail light....crazy. Any way mine was under warranty but it would have been over $300 for me fix on my own. This was on a 2016 4Runner so it may be cheaper for your truck???

 

Fair enough. Don't hesitate to reach out to any one of us at any time.

 

@BubbaW I have my suspicions this is electrical related, maybe moreso than 4WD. Got a sec to throw eyes on it?

 

Do you have a scanner that is capable of reading ABS codes? Or do you have a scanner that can read each individual wheels speed? Maybe that could help determine if it is somehow related to a wheel speed sensor.

 

Try this...

 

I'm afraid that I have a somewhat basic scanner. I know that I do not have a scanner that can read each individual wheel speed. You are giving me a good idea to have my indie mechanic drive it around and tell me if each wheel is reading uniform and to run a scan on ABS codes. It would be worth the diag fee in my opinion. Thanks for the tip.

 

While I do have the 05-06 FSM for Sequoia, it does not have good electrical diagrams like our Tundra FSM’s. Other than being a bystander, about all I can suggest is that @Scuddog revisit his TR-42 continuity checks, something with those checks don’t sound kosher as I read it in the Sequoia FSM. With this extra Sequoia Diff Lock button, compared to Tundra, I’m a peanut gallery member. As usual, @N84434 has the jack up testing covered.

 

There must be a difference with the 2001 system. When I was having ABS problems last year, I didn't have any discernible problems with the 4WD System. I'm assuming that 04-06 perhaps is different?

 

I'm not sure honestly. Someone mentioned it could be somehow related so it would be an easy check just to confirm if he had the right scanner for it.

 

My indie mechanic down here has the advanced scanner diagnostics. I will ping him in a few weeks. Thanks Bubba... I also do not like how two of the switch continuity tests were not according to manual spec. Something is off there.

 

Maybe this will help.

 

EvilMilkshake, thanks. Over 300 pages! Wow. And the Sequioa is a dinosaur compared to modern vehicles. I wonder how many pages a new car's manual would contain? Anyway, thanks. I will search for 4x4 pages and check them out. I'm still not comfortable with my switches failing two of the continuity tests that I did last weekend.

 

Update... A thousand miles on the road in 4HI have only proven to be annoying with the flashing lights on the dash. My gas mileage is abysmal and that has sucked. About a month ago, I jacked up all four corner and used two jacks for safety. It was rock solid on the jacks but I was still cautious and respectful of the fact that 5000+ pounds were in the air. My son sat in the driver's seat. I slid under the transfer case and used a plastic coated mallet to whack on the transfer case/actuator. I did it while the tires were idling in forward and reverse. Nothing. I did it while in neutral. Nothing. After whacking on the actuator for a bit of time I gave up. Crap.

I took the Beast to my indie mechanic and he did a courtesy look to see if rats had chewed on some wires. All of the wires under the entire car were intact with no sign of rodent chewing. He admitted that he did not have experience working on 1st gen Toyota 4x4 systems.

So, I have an appointment at Key West Toyota next week. I am willing to pay the diagnosis fee to see what those mechanics think and will update the forum when I receive an answer. It's frustrating but I'm out of options for a few months so I need to keep trying to get this fixed. Stay tuned!

 

Please let us know. I have a 2004 DC Tundra and I get the flashing Hi lights all the time, constant now. My 4WD engages and disengages but the light is annoying. I tapped on the actuator too to no avail. An Army mechanic that had a 1st Gen Tundra told me it could be the sensors but he said they're a pain in the butt to get to. Anyway, hoping there is a solution to this without paying thousands to Toyota place.

 

You can take it to a dealership and pay them just to run the diagnostics and tell you what they think is wrong with it. Then either do the work yourself, or take it somewhere they won't charge you an arm and two legs.

 

Two techs at KW Toyota took pity on me when I took it in two weeks ago. I should have updated this forum but was overcome with Hurricane Ian. Anyway, one tech did a pin-test and determined it was the transfer case. The other tech has owned three 1st gen Tundras and also came to the same conclusion about the transfer case/transfer case actuator. They did not charge me because they said that rarely do they get anyone in the service bay that has gone to the lengths that I have to figure this out. I printed them a one-page note and taped it to the dash. I explained everything that I had done and everything that I suspected. They were impressed with the front diff actuator job and agreed that would have been their likely first action as well. Both of them said that I am fine to drive my Sequioa stuck in 4HI as I have a different 4WD system that allows me to drive on pavement. If I had a traditional 4X4 system that binds on pavement, I'd be screwed.

So.... I'm going to simply drive my truck with the flashing lights hid behind a picture of my family. No way in hell am I spending money to have the transfer case/actuator replaced. My truck is already a total loss from a RV-jackknife incident. She has served me well and I will continue to maintain her otherwise, but I'm not able to bring myself to spend the money to fix an issue that would cost more than this truck is worth. Everyone in this forum has been great and I will continue to engage throughout the forum.

 

Hey Scud, glad you made it past Ian still kickin'.

I guess it's not necessarily a happy ending here, but ... at least there's an answer.