Diff Lock Indicator flashing when truck started and while driving (1 Viewer)

[JeffH]

Found this thread after my 2010 LX did this twice in the past week (~82k miles). Mine does not reset after turning off engine and restarting, it does though after I've driven somewhere and then restarted. Maybe engine heat is needed to fully warm it up, although it was only 45F this morning so not very cold. I have not tried cruise or 4Lo when this happens. I did have an issue with 4Lo not engaging when I bought it and after flushing it twice it works every time now, since the PO never used 4Lo I'm sure CDL never was used as well. Will try to exercise it and see what happens.

 

[linuxgod]

Found this thread after my 2010 LX did this twice in the past week (~82k miles). Mine does not reset after turning off engine and restarting, it does though after I've driven somewhere and then restarted. Maybe engine heat is needed to fully warm it up, although it was only 45F this morning so not very cold. I have not tried cruise or 4Lo when this happens. I did have an issue with 4Lo not engaging when I bought it and after flushing it twice it works every time now, since the PO never used 4Lo I'm sure CDL never was used as well. Will try to exercise it and see what happens.

You are correct that restarting right away when cold typically doesn't clear the flashing. In my experience you need the transfer case to warm up a bit. Then if you shut the truck off and back on it goes away. Driving it until the engine is up to operating temp and shutting it off and then restarting should do the trick.

FWIW I don't think that exercising it has a huge impact, unless maybe you're exercising it every day. I was exercising the CDL for short distances and even ran it for about 10 miles in the snow on paved roads recently. Then mine came on again a couple weeks later when it was around freezing, but hasn't come back since. I intentionally haven't exercised the CDL since the light came on as I want to take it to the dealer since it's under warranty and I'm kinda waiting for the problem to happen consistently.

 

[Docboy]

Happened to me once during the winter when I left the vehicle outside. Freaked me out too, but it went away after I shut off and restarted the truck.

I also try to "exercise" the diff lock (and 4lo) every few days.

 

[linuxgod]

Flashing CDL popped back up last Friday (4/13) about 8:50am. Outdoor temp was 45F. Vehicle was cold. Drove the kids to school (3/4 of a mile, took about 4 min) and shut the vehicle off just as it was starting to warm up a bit. When I came back 10 minutes later and restarted it was fine.

For posterity I took a video of this last summer in Breckenridge. When this happens pressing the CDL button does nothing. Also putting the truck in Neutral and shifting to 4Lo does nothing (the transfer case does not click, the 4Lo light doesn't come on or flash, the 4Lo menus never appear in the MID, and if I put the vehicle into drive it is absolutely still in 4Hi). Interestingly this was the morning after we did Peak 10 at night, in which I had engaged 4Lo and the CDL (but I hadn't used them for a couple months previously). So I'm not convinced that "exercising" the system prevents this at all.



I went to the dealer yesterday with this on my punch list and of course they could not reproduce it. I showed the service manager the video and he agreed it was an issue, but fuses and relays all checked out fine, there were no codes stored in the system, and without it occurring for them they are unable to do the full diagnostic tests which check for voltage and resistance in the transfer case actuator assembly and ECU to determine where the problem lies. At the moment this is just an annoyance but I always have that fear in the back of my mind that if there's an actuator issue (sticking, bad internal electrical connection, etc) I'm going to be the unlucky guy who has it fail completely while on a trail.

Next time this happens I'm going to go get my laptop and OBD2 cable and fire up TIS Techstream to capture all the values in Powertrain / Engine and ECT / Data List.

I wish there was a good Toyota resource which (or who) could explain what self-tests are happening at startup. Because the CDL light happens within 1-3 seconds of starting the truck, there must be some sort of self-test failing or some invalid voltage or resistance on one of the circuits. If it immediately cleared on cold restart I would suspect a bad ECU. Given that the vehicle needs to warm up a bit before it clears, and that the issue is affecting the CDL and 4Lo, I'm suspecting the transfer shift actuator more and more.

 

[linuxgod]

In the event anyone else with this ongoing issue would like to review the troubleshooting procedure, I'm going to post it here. A bunch of screenshots so it might take a few posts:

 

[linuxgod]

 

[linuxgod]

 

[linuxgod]

 

[SWUtah]

I have the same thing happening on my 2015 with 31,000 miles only happened twice I think it’s a moisture issue and the temperature fluctuation causes it once it gets warmed up no moisture, being in Florida lotta rain this time a year and then sitting and the moisture gets up there could be what’s causing the issue? Did it again this morning 85 degree drove a block turned off and back on it went away

 

[SWUtah]

So from reading this thread, dealers just say they can't reproduce and bring it back while it is flashing. When brought back when it is happening the dealers can't figure out how to fix even though linuxgod show S the procedure from the service manual. So the conclusion is since it is nothing more then a light coming on and it goes out after the engine warms up then it's just an annoying light and everyone just ignores it? Since it won't cause any mechical or driving damage or problems? If this is true then when it happens on a day during my local Lexus dealers service hours and I have nothing better to do I should drive to the dealer keep my LX running and have the service writer or manager come out to witness it, explain that I know their is a trouble shooting procedure in the service manual and I want it tracked down and corrected and I don't want to hear that the problem could not be reproduced!!! Since that is why I drove it to the dealer to witness the light being on. So do you guys think this will get my light issue fixed?

 

[linuxgod]

I took a detailed video and the dealer still said they can’t diagnose without it happening to them since there were apparently no codes in the system. They did record it though so if I have an issue post warranty Toyota should cover it.

 

[SWUtah]

I took a detailed video and the dealer still said they can’t diagnose without it happening to them since there were apparently no codes in the system. They did record it though so if I have an issue post warranty Toyota should cover it.

Thanks so my plan of driving it to the dealer when it happens and having them come out and witness the light being on and then asking them to either fix it or notated in my file in case I ever have a problem I’ll do that appreciate your help

 

[linuxgod]

My recommendation is to take a video, try to get your mileage and VIN and the date in the video, and walk/talk through reasonable troubleshooting you're doing in the video, which is what I did:

• I just started the vehicle, it's 8:30am, it's 45F out, the vehicle was cold and had sat overnight, it was working yesterday, and now the CDL is flashing
• I shift to N, attempt to put it in 4Lo, nothing happens, shift to drive and reverse and we are obviously still in 4Hi, I shift back to 4Hi.
• I press the CDL button, nothing happens (light keeps flashing).

Other things to potentially do after you've done the above.

• Show the VIN and the mileage on the video
• Turn the vehicle off and back on. Most likely the light keeps flashing since the drivetrain is cold.
• If you can't get to a dealer, drive 5-10 minutes until the vehicle warms up. Turn it off and back on. Most likely the light will go out. You can then cycle through 4Lo and the CDL above correctly.

In theory the above should prove it's an issue with the actuator and not the sensor, particularly when it repeats after a restart. Of course what the dealer wants is a stored code in the ECU they can pull which says "transfer case actuator malfunction" or some such thing.

 

[SWUtah]

Great advice and information thanks

 

[Taco2Cruiser]

I mentioned this in another thread, not saying this is the cure, just my experience.

Bought a 2011 used with 75k miles. Center diff was never locked from previous owner, and work just fine for half a year, getting used a lot.

Switched the factory fill t-case fluid to a GL-5 75w-90 gear oil. Started getting these issues. Cold starts, the CDL would flash... and so on. Even going down the highway, CDL would start to flash.

Switched back to Toyota 75w LF. Issues stopped, and have not come back.

Oil background. Toyota 75wLF, we need to stop looking surface level at fluids, viscosity matters, but there’s so much more. Buy any 75w-whatever synthetic gear oil, it’s probably GL-5. That means it’s slippery. Like, that’s its main purpose, to be slippery, because it’s gear oil, you want that.

But our transfer cases (only mid 2010 and newer) started to require a low friction oil. Which is not slippery, but uses a much different molecular make up to reduce friction without being like KY jelly cranked to 11. In fact, a component requirement that wants a LF oil is a tell tale sign that slippery is going to hinder. Newer manual transmissions have already gone down this path, sure they used to require gear oil, but that’s not the case anymore. I believe the 200s newer t-case is the same way. Manufactures changed in mid 2010, and so did the oil requirement. But this isn’t like an engine going from 5w-30 to 0w-20, where they both require API SN oil, this is deeper. I think the slipper GL-5 gear oil is allowing something to slide into or out of lock, but the required LF oil that it’s designed for, is allowing something to stay put.

Do with that as you will, like I said, my problems with this was from a high quality synthetic GL-5 gear oil. Went back to Toyota’s 75w LF (low friction, not to be confused with their gear oil, which is names LT) and haven’t had another problem for 30,000 miles. Cold, hot, towing, rock crawling, and lots of highway.

 

[gaijin]

I mentioned this in another thread, not saying this is the cure, just my experience.

Bought a 2011 used with 75k miles. Center diff was never locked from previous owner, and work just fine for half a year, getting used a lot.

Switched the factory fill t-case fluid to a GL-5 75w-90 gear oil. Started getting these issues. Cold starts, the CDL would flash... and so on. Even going down the highway, CDL would start to flash.

Switched back to Toyota 75w LF. Issues stopped, and have not come back.

Oil background. Toyota 75wLF, we need to stop looking surface level at fluids, viscosity matters, but there’s so much more. Buy any 75w-whatever synthetic gear oil, it’s probably GL-5. That means it’s slippery. Like, that’s its main purpose, to be slippery, because it’s gear oil, you want that.

But our transfer cases (only mid 2010 and newer) started to require a low friction oil. Which is not slippery, but uses a much different molecular make up to reduce friction without being like KY jelly cranked to 11. In fact, a component requirement that wants a LF oil is a tell tale sign that slippery is going to hinder. Newer manual transmissions have already gone down this path, sure they used to require gear oil, but that’s not the case anymore. I believe the 200s newer t-case is the same way. Manufactures changed in mid 2010, and so did the oil requirement. But this isn’t like an engine going from 5w-30 to 0w-20, where they both require API SN oil, this is deeper. I think the slipper GL-5 gear oil is allowing something to slide into or out of lock, but the required LF oil that it’s designed for, is allowing something to stay put.

Do with that as you will, like I said, my problems with this was from a high quality synthetic GL-5 gear oil. Went back to Toyota’s 75w LF (low friction, not to be confused with their gear oil, which is names LT) and haven’t had another problem for 30,000 miles. Cold, hot, towing, rock crawling, and lots of highway.

Very true - thanks for posting.

 

[linuxgod]

I mentioned this in another thread, not saying this is the cure, just my experience.

Bought a 2011 used with 75k miles. Center diff was never locked from previous owner, and work just fine for half a year, getting used a lot.

Switched the factory fill t-case fluid to a GL-5 75w-90 gear oil. Started getting these issues. Cold starts, the CDL would flash... and so on. Even going down the highway, CDL would start to flash.

Switched back to Toyota 75w LF. Issues stopped, and have not come back.

Was your half a year of no issues during the warmer months? I have noticed it only happens to me when the temps dip into the 40s or below. No issues for 6 months each summer, except when I visit Colorado in the summer and the overnight lows in the mountains are in the 40s it's guaranteed to happen again (even if I used the CDL and 4Lo the day before), but around this time of the year the issue starts up again.

I've had the same thought about fluid since I went to using diff oil in the transfer case, but mine was happening before I did the transfer case swap, and I'm fairly sure at 2 years/49k miles it had factory fluid in it.

 

[Overland Tailor]

I know most people say that working the Center Diff didn't resolve the problem, but on my wifes LX570 it did.

Every morning when the truck was cold (Ambient in the 60's here in BHM) the light would flash until the truck was restarted. I then operated the Center Diff on and off a few times when I would drive the truck (About 6 times in 2 weeks) and I've not had the issues again. Its been cold here with the overnights in the low 30's and still no light. Its been months since I've seen it.

Hopefully exercising the Center Section will help some other people.

John

 

[Taco2Cruiser]

Was your half a year of no issues during the warmer months? I have noticed it only happens to me when the temps dip into the 40s or below

No it was during the winter. If fact some of it was camping in the 20s for a few weeks.

My issue came when I switched the fluid over to gear oil in El Paso and drove easy to Savannah in the spring and summer months.

 

[Sandroad]

Anyone have an update on this issue? My '17 has started flashing the 4lo and diff lock indicators on cold start (but not every time) with ambient temps in the 40s. No stored or active OBDII codes and everything drives normal (except of course no 4lo or diff lock available while flashing). Looks like most others have ended up ignoring it and accepting the glitch (if that's what it is). Each summer I use both features a couple times a month, so I know those work well when the lights are not flashing.