VSC TRAC / VSC OFF after maintenance

[2001LC]

I always get ABS and/or brake light if a brake issue like fluid level, pressure, pump, motor, acuumlator, wheel speed sensor, etc.

First thing that comes to mind is it all started after changing the spark plugs. I always look for issues that may have been caused by last job first thing. Since no misfire code I'll assume plugs and coils installed correctly.

Next would be vacuum lines. In pulling coils & plug air box comes off, and so vacuum hoses are unplug or disturbed. A 01 with 171K miles would pretty much need all new vacuum lines. This includes PVC grommet, valve and both hoses. But these would not give DTC your getting. But we've a double line coming off vane pump idle control. These line might set of the DTC you have. They will without doubt set of VSC ect, most anything will. Often time these line are not plugged back in as we button up after pulling air box. But even if plugged back in they've been disturbed. Remove/disturb old rubber vacuum lines, they tend to crack and no longer seal well, cold weather also will worsen this. Sometimes we can cut off first few inch of a rubber hose/line as a temporary fix too test.

Additionally, it's best practice to disconnect battery when removing any electrical connection. This is true of the MAF. I always like to clean and grease battery post & clamps when cleaning MAF & throttle body. I start by disconnect negative battery post and last thing I do is connect negative post. I make sure battery disconnected for 20 minutes minimum, this reset ECM. Toyota engineers are now (200 series) advising to disconnect battery when using external charger on battery. I feel this a good Idea for the 100 also.

Zero point can also be done by driving in straight line at 35 MPD for a few 100 yards. But I'd have to go back and look at my 01 FSM to see if that worked.

I'd look over all these things and see if any issue show up that need attention. Also take a hard look at front end. i.e. steering rack, TRE, FDS (CV's), wheel bearing, ball joints, etc. for play. Once good on this basic stuff, then clear DTC's. If DTC come back follow the digicnotic tree in FSM to the letter.

BTW: I change the double vacuum line on about every rig, even low mile 07's these days, with OEM replacement.

Good luck hopefully and easy fix.

BTW: I use www.partsouq.com a lot for the diagrams by punching in my VIN #. It can help when trying to find parts used in conjunction with the FSM.

 

[2001LC]

Toyota sells a bag of 2' (best value) section of vacuum line you can cut for others. PN # 90999-92003

 

[Pyrenees]

@2001LC

Thanks for the valuable info! You are correct, this all started when I replaced the spark plugs. Granted, I replaced the spark plugs only a few hundred miles after purchasing the car, so it's entirely possible that this problem existed before I bought it.

I did try and check all of the vacuum lines that I had removed during the process. I actually replaced one as well. I'm not sure I saw that enormous one, but I'll have to look and see where the heck that goes.

The only code I seem to ever set anymore is C1234 yaw sensor calibration undone, or whatever it is. The other codes cleared after I plugged the MAF back in. I really want to test the yaw sensor but I only have a vague idea of where it is located. The FSM has a test procedure for it, I just need access to the sensor. It's somewhere under the center cluster I think.

I haven't had any running issues, just replaced the spark plugs due to not having a service record of them being done already.

How did you get your intake manifold so clean?

 

[fjman]

My vsc/trac light comes on about once a month. When I stop and restart the truck next time I’m heading out it’s not illuminated. It did it more often when I first bought it but not it’s pretty rare.... I just figured it was one of those getting older quirks!

 

[2001LC]

@2001LC

Thanks for the valuable info! You are correct, this all started when I replaced the spark plugs. Granted, I replaced the spark plugs only a few hundred miles after purchasing the car, so it's entirely possible that this problem existed before I bought it.

I did try and check all of the vacuum lines that I had removed during the process. I actually replaced one as well. I'm not sure I saw that enormous one, but I'll have to look and see where the heck that goes.

The only code I seem to ever set anymore is C1234 yaw sensor calibration undone, or whatever it is. The other codes cleared after I plugged the MAF back in. I really want to test the yaw sensor but I only have a vague idea of where it is located. The FSM has a test procedure for it, I just need access to the sensor. It's somewhere under the center cluster I think.

I haven't had any running issues, just replaced the spark plugs due to not having a service record of them being done already.

How did you get your intake manifold so clean?

Sound like you have the basic covered.

That "enormous" is just a PCV hose of which we've two; PS & DS. But as noted this would not set off these DTC. A weak battery could, but yours sound pretty good. Although I like ts see 13.2 V on my charger after a full 100% charge.
In the link I provided you "partsouq" above, punch in your VIN #, I looked under Electrical, ABS-VSC. I see 8918060030 SENSOR YAWRATE and 8944060120 SENSOR, DECELERATION close to each other. Does look like under under center console, but hard to tell. I'm looking at with my 00LX VIN, which is probably the same but my be different for your VIN #. In FSM it looks more like in RH footwell side cowling or behind glove box or under hood RH fender well. I also see FSM has us checking at wire housing blocks. Find which blocks is just a PITA, as FSM is rarely clear on which one. It takes a lot of digging.

Wish I could be more help, but only time I saw this code, cleaning up battery and full charge over 13V cleared it up. I always clean and grease those battery post & clamps.

I use degreaser, brushes and high pressure water to clean engine. I use care not to damage soft stuff with HP water, avoid electric housing and I don't get to much water on top of engine or between head and intake. Once done I fire up the engine and drive until dry. Water can get into intake port of heads through the intake gasket or lower seal of injectors so I'm careful and I also use compress air to dry these ares. Anytime I'm pulling intake I like area really clean so sand/crud doesn't get into ports.

 

[Pyrenees]

Sound like you have the basic covered.

That "enormous" is just a PCV hose of which we've two; PS & DS. But as noted this would not set off these DTC. A weak battery could, but yours sound pretty good. Although I like ts see 13.2 V on my charger after a full 100% charge.
In the link I provided you "partsouq" above, punch in your VIN #, I looked under Electrical, ABS-VSC. I see 8918060030 SENSOR YAWRATE and 8944060120 SENSOR, DECELERATION close to each other. Does look like under under center console, but hard to tell. I'm looking at with my 00LX VIN, which is probably the same but my be different for your VIN #. In FSM it looks more like in RH footwell side cowling or behind glove box or under hood RH fender well. I also see FSM has us checking at wire housing blocks. Find which blocks is just a PITA, as FSM is rarely clear on which one. It takes a lot of digging.

Wish I could be more help, but only time I saw this code, cleaning up battery and full charge over 13V cleared it up. I always clean and grease those battery post & clamps.

I use degreaser, brushes and high pressure water to clean engine. I use care not to damage soft stuff with HP water, avoid electric housing and I don't get to much water on top of engine or between head and intake. Once done I fire up the engine and drive until dry. Water can get into intake port of heads through the intake gasket or lower seal of injectors so I'm careful and I also use compress air to dry these ares. Anytime I'm pulling intake I like area really clean so sand/crud doesn't get into ports.

I legitimately had a dream last night where my battery terminals were loose, haha. Ah, god. So, the battery is from 2016 and I've had zero performance issues with it. DC gauge in the cluster is always around the 3/4 mark. We used to have a Volvo that was sensitive to non-perfect batteries so I get where you're coming from. I kinda don't think it's the battery/alternator in this case but I will absolutely hit the terminal with a wire brush and grease because I've got nothing to lose. I've never greased them before, is this just something they sell in a packet at the store? What kind is it?

 

[2001LC]

I legitimately had a dream last night where my battery terminals were loose, haha. Ah, god. So, the battery is from 2016 and I've had zero performance issues with it. DC gauge in the cluster is always around the 3/4 mark. We used to have a Volvo that was sensitive to non-perfect batteries so I get where you're coming from. I kinda don't think it's the battery/alternator in this case but I will absolutely hit the terminal with a wire brush and grease because I've got nothing to lose. I've never greased them before, is this just something they sell in a packet at the store? What kind is it?

If you cleaned post they're good for awhile. Grease stops oxidation on the lead post, without it resistance goes up as oxidation builds and AMP throughput goes down. I use White lithium grease, but when it's gone I'm switching up to the red stuff. They sell it in little package anywhere batteries are sold, which comes in a larger can from CRC also. Any grease even vaseline works in a pinch.

 

[Pyrenees]

I have some CRC electric cleaner spray stuff in a can in the shed, no idea if it's what you're talking about though?

 

[2001LC]

I have some CRC electric cleaner spray stuff in a can in the shed, no idea if it's what you're talking about though?

No, but that good stuff for cleaning electrical contacts. Use it, then dielectric grease on your wire contracts as you go hunting for this C1234 issue.

Keep in mind with your battery holding good charge I doubt this is your issue.

I always clean battery with baking soda to neutralize acid.

Then I clean and grease post. Been using White Lithium Grease for many years

I've yet to use the packet stuff like this

Nor have i yet to use CRC can like this

 

[Pyrenees]

@2001LC - I took your advice and cleaned up the terminals/connectors... I figured it's a good thing to do even if it doesn't affect my VSC/TRAC light issue. There was no corrosion on the positive terminal. The negative one didn't look that bad but after removing it I got some corrosion out. Had some white lithium grease so I used that.

Later on the same day, I got the VSC/TRAC + TRAC OFF combination, again when I quickly rowed the shifter from D to P after a drive. The lights turned off on their own by the next time I drove the car, which has become the standard behavior ever since I did a zero-point calibration. I truly think something about the PRNDL light circuit is tripping up the VSC/TRAC circuit. My D bulb is burned out but the rest are fine.

 

[2001LC]

@2001LC - I took your advice and cleaned up the terminals/connectors... I figured it's a good thing to do even if it doesn't affect my VSC/TRAC light issue. There was no corrosion on the positive terminal. The negative one didn't look that bad but after removing it I got some corrosion out. Had some white lithium grease so I used that.

Later on the same day, I got the VSC/TRAC + TRAC OFF combination, again when I quickly rowed the shifter from D to P after a drive. The lights turned off on their own by the next time I drove the car, which has become the standard behavior ever since I did a zero-point calibration. I truly think something about the PRNDL light circuit is tripping up the VSC/TRAC circuit. My D bulb is burned out but the rest are fine.

The battery terminal greasing stops oxidation. This oxidation is hard to see, it's Just a slight graying (dull silver look) of the lead post. Once clean with wire post cleaner or sandpaper they're a shiny silver losing dull (oxidation) look.

Most everyone's "D" light is out.

I suppose it could be shifter position sensor, but seems you get more DTC. Most anything will set off the VSC/TRAC + TRAC OFF combination, they come on a lot. IIRC even turning on the CDL will do this, brake ABS issue, Airbag issue the list is long.
Did you find the YAW RATE SENSOR?

This picture show in on same side of vehicle as DCL1 (PS). Looks like PS foot well but could be under hood. FSM is fustring sometimes.

 

[2001LC]

Found it: Y 1, 2001 Land cruiser FSM (EWD426U) EWD page 41

 

[Pyrenees]

I guess that would mean the yaw sensor is behind the panel where the cig lighter is, probably bolted to the top of the tranny tunnel. That is a pretty tight spot (I was just in there doing a big stereo upgrade).

Something that I just noticed is that in one of your pics there is indeed a label for the VSC warning buzzer. I wonder if it simply unplugs. I am going to check on that. I don't mind the flashing traction control slip warning light, but the BEEP BEEP BEEP BEEP BEEP BEEP aspect is nuts to me. It's one thing if you forget to set the flaps on final approach, it's another thing if my steering rack bushings are a little out-of-spec

 

[2001LC]

******* **** BEEP BEEP BEEP BEEP BEEP BEEP aspect is nuts to me. It's one thing if you forget to set the flaps on final approach, it's another thing if my steering rack bushings are a little out-of-spec

Better than ELT beeping on impact of crash...

 

[Pyrenees]

Better than ELT beeping on impact of crash...

Well at least there's a decent chance you won't ever hear your ELT...

 

[Pyrenees]

My god, there it is. VSC skid buzzer is a little black box clipped to the side of the ABS/VSC/TRAC ECU and it looks like you can unplug it. Located under the driver's dash above the dead pedal. P/N 86652-51010 is on the side, looked it up to confirm. This is a game-changer.

 

[2001LC]

Well at least there's a decent chance you won't ever hear your ELT...

I heard it once, not fun!

 

[Tummler]

I just dealt with this issue. I dug out my old laptop with Windows XP and Techstream (which took 3 hours to get it to boot) and went to work diagnosing the situation.

Nothing was making sense. Several error codes that didn't appear to bear any relationship to one another. One code concerned a secondary air valve that failed.

As I was running tests, the media center went dark. I was thinking "oh s***, I just shorted it out." Then it dawned on me that all the symptoms could be the product of inconsistent electrical power. Sure enough, the engine wouldn't turn over when I attempted to start it up.

Replaced the battery (approximately 4 years old) a couple weeks ago, and I haven't had a problem since.

I saw that you ran the battery down while working on your Land Cruiser, but that you observed an adequate voltage reading after recharging it. Are you 100% positive your battery is in good shape? I'm not a fan if throwing parts at a problem, but if your battery is a couple years old or older, I would strongly consider replacing the battery, if for no other reason than to rule it out as a cause of your issues.

 

[Pyrenees]

@Tummler - I'll put it this way, I have no strong evidence to suggest the battery is in sub-par shape. It's also two years old. When I ran the battery down it was completely my fault. I had a lots of lights on, engine off for a long time, etc. I've been down the road of weak batteries/alternators before (on different cars, not my 100) so I'm pretty used to what all of that mess looks like, and I'm just not seeing those warning signs in this case. I'll know for sure when the first frozen morning hits and it either cranks poorly or not

 

[2001LC]

Ok, so we come back to "Always look to last work done first" when new issue starts after.

Any alteration to wires or adds to factory configure is first place to start looking. Just getting into dash or console area you may have loosened a wire plug/housing. Doing so with battery connected can case issues, especially if key turned on!