Electrical Issue: VSC, Brake, Multi Terrain

[Hltoppr]

So, I'm a couple hours South of the US border in Mexico, and after a couple of mild "whoops" where sand had blown onto the road, I brake and the dash lights up like a Land Rover. ABS, VSC, and Brake lights come on, dash reads Multi Terrain Select Not Available, and the temp, tach and speedo gauges go to zero.

When the brake is not depressed, gauges work as normal, and the Brake light turns off. Terrain Select (green) light blinks.

I'm thinking I've lost an ABS sensor. Truck starts and drives just fine otherwise. No visible damage to ABS sensors at each wheel or the wiring. No codes read on the reader, and all systems otherwise operating normally.

I'm a few days out from a dealer. Not too worried, but open to ideas.

-H-

 

[Jhalko]

I'm thinking I've lost an ABS sensor. Truck starts and drives just fine otherwise. No visible damage to ABS sensors at each wheel or the wiring. No codes read on the reader, and all systems otherwise operating normally.

I'm a few days out from a dealer. Not too worried, but open to ideas.

-H-

Sounds like you've diagnosed it based on the symptoms and what plenty of other folks have experienced. I thought the only way to confirm the abs sensor wire was bad was with a meter.

 

[Hltoppr]

Lol...with a new truck I got away from carrying a full tool kit and parts bin.

No meter with me.

-H-

 

[rigtec]

"...So, I'm a couple hours South of the US border in Mexico, and after a couple of mild "whoops" where sand had blown onto the road, I brake and the dash lights up like a Land Rover. ABS, VSC, and Brake lights come on, dash reads Multi Terrain Select Not Available, and the temp, tach and speedo gauges go to zero."

-H-

Hi Hltoppr,

If a similar situation hadn't plagued my truck just a couple of years ago I wouldn't have picked up on your description of the problem! You see, your trouble isn't just limited to your brake system... it crossed over to the instrument cluster with the tach, speedometer and temperature gauge which tells me that this has nothing to do with wheel sensors. These symptoms reveal that the 'Main Body ECU COMPU Net' isn't reading the intel being generated by your sensors, but generating it's alarms from within.

When my instrument cluster lit-up with many DIFFERENT system failures, no one could/would take it into their shop because of the complexity of it's symptoms; even my Toyota dealership (where I made the purchase of the 4R) were saying it was caused by my aftermarket accessories e.g., fogs, subwoofer system, H.O. Alternator... which was just a (poor) scheme of wiggling out of doing any work under warranty. And the local, NON-dealership mechanical shops just didn't know how to approach this unusual trouble!

I was on my own from then on to study the truck's electrical/electronic systems and learn how these systems are connected and integrated to work together. Long story short... in your case, it looks like the main body ECU has lost one of it's power supplies; I know there are AT LEAST 7 that I've seen, here is the list:

MAIN UNDERHOOD FUSEBOX:

#34 ECU-B 10A
#26 SHORT-PIN (not a fuse; but a bridge between electrical busses)

D/S (SECONDARY) FUSEBOX near e-brake

#10 multiplex communication system 30A
#14 ECU-IG #2 10A
#16 ECU-IG #1 10A
#21 OBD (On-Board-Diagnostics) 7.5A
#23 D/L #2 (multiplex communication system) 25A

 

[wfo9]

Get under there and check the connectors. They are easy to reach. Make sure they are seated properly...

Is this a 100% stock truck...? A little unusual for it to go bad without someone installing lift...

One of the brackets on the passenger side on mine had the wire smashed from the factory where it connected to the UCA. When I removed the bracket to install aftermarket UCAs.. the wire failed.

 

[rigtec]

"...So, I'm a couple hours South of the US border in Mexico, and after a couple of mild "whoops" where sand had blown onto the road, I brake and the dash lights up like a Land Rover. ABS, VSC, and Brake lights come on, dash reads Multi Terrain Select Not Available, and the temp, tach and speedo gauges go to zero."

-H-

Hi Hltoppr,

You need to pull out every one of these fuses "One at a time" and check each one with a continuity tester including the short-pin (which isn't a fuse) but should still be checked for continuity and then returned to it's original position if it checks out! When you are finished testing all seven of these current carrying devices and have returned them to their assigned slots, start the truck as you normally would and see if the problem has been resolved. If it has been resolved then the trouble was just the pins were making poor contact with the slot's contact.

If the problem still exists, disconnect the NEG battery terminal and leave it disconnected for a minimum of four hours to RESET all of the ECU's so that they can go back to their factory preset parameters. After you do that, the problem 'SHOULD' be resolved! Please be sure to let us how you made out either way so we will all learn from this experience, 'Best to you'

rig, cheers!

 

[Hltoppr]

Guess I've got some checking to do! Not a stock truck, but the only changes to the systems include a Toytec 2" TRD Pro lift, along with a National Luna system for the second battery. Nothing attached to the main battery.

I visually looked at the fuses, both under dash and engine bay, and found nothing obviously blown. Might try to find a tester locally and give it a go.

-H-

 

[AZrunner11]

ABS Sensor

It's weird that when the brake isn't pressed, the lights go off. I had an ABS sensor wire damaged during the CV axle trail fix and i had the same indicator lights come on- dash looks like a christmas tree and multi-terrain select was disabled. Good Luck

 

[TRDproMGM]

I had an ABS sensor damaged during the Toytec TRD Pro 2" lift as well and saw everything your seeing except for the correlation of the brake push and Speedo/Tac weirdness. The shop fixed the ABS sensor after ordering parts and all is well now. The brake thing is definitely an oddball and making me think it's something else after spending hours research ABS sensors and 5th gens from my issue. Did it happen right after lift install or later? After reading rigtec's post I'd try that.

 

[Hltoppr]

Heading into the nearest town this morning to find a multi meter. Lift was recently installed, about a month ago, but this is the first time the suspension had seen any actual flexing.

Thanks so much for all the help so far!

-H-

 

[fbksurferjoe]

I too broke my abs sensor wire and instantly had the lights. I think you might have something else going on due to the gauges and other symptoms you described. if it is the wire it is any easy repair if you know how to solder.

Sent from my SM-G920V using Tapatalk

 

[rigtec]

Guess I've got some checking to do! Not a stock truck, but the only changes to the systems include a Toytec 2" TRD Pro lift, along with a National Luna system for the second battery. Nothing attached to the main battery..."

Hi Hltoppr,

First, I'd like to apologize for my previous post being published twice! While I was typing, the screen vanished (just gone)! I started looking for it but didn't know that it had been submitted. When I hit the back button, the unfinished screen reappeared so I proceeded with my statements. It wasn't until I completed my post and submitted it that I realized it had already been submitted :noidea: lol!

I seriously doubt that the problems you describe in your original thread topic have ANYTHING to do with the mods that you may have added to the truck... the ECU's in these 'War Tanks' will pretty much take all that you can dish out, provided the sensor wires remain un-cut at any time!

I visually looked at the fuses, both under dash and engine bay, and found nothing obviously blown. Might try to find a tester locally and give it a go. -H-

As far as using the OBD-II port for testing... don't forget that because of the notification that says: "Multi-terrain Select NOT AVAILABLE", that's an indication that there may be 'no communication' or 'limited communication' between ECU's with each other, or the OBD-II port in the vehicle. This is not a huge concern, only more evidence that one of your ECU's has lost it's power supply (There may be between 20 and 25 ECU's or more)! Again...

Check ALL of your fuses using a 12v test light ($5 bucks) or use a multi-meter set to DCV, low range, with the IGN switch in the ON mode. Connect the negative lead to a good ground. Now begin using the RED probe to touch the fuse prongs (rear end of the fuses); you should see 12V on BOTH sides of every fuse that's HOT on the line-side! Take your time with this so as not to miss or overlook the one fuse that is bad or... has lost contact with the slot contacts!

rig, Cheers!

 

[Hltoppr]

Looks like I found the likely culprit. After going through all the underhood and inside fuses, the ETCS (Electronic Traction Control System) fuse in the engine bay was likely loose. Pulled it out, tested continuity, and replaced it and all seems to operate as it should.

Terrain Select and locker all working, and dash lights are resolved.

Thanks so much to all who helped! (Rigtec especially!) Saved a ton of time in an area where I've got limited resources! The Tecates are on me when we meet someday!


-H-

 

[rigtec]

Looks like I found the likely culprit. After going through all the underhood and inside fuses, the ETCS (Electronic Traction Control System) fuse in the engine bay was likely loose. Pulled it out, tested continuity, and replaced it and all seems to operate as it should.

Terrain Select and locker all working, and dash lights are resolved.

Thanks so much to all who helped! (Rigtec especially!) Saved a ton of time in an area where I've got limited resources! The Tecates are on me when we meet someday!


-H-

Much Blessing to you and yours brother! ...And thanks for the fast and detailed feed back; so glad you were able to locate the 'power supply loss' so quickly! 'Best to you',

rig

 

[Jhalko]

Much Blessing to you and yours brother! ...And thanks for the fast and detailed feed back; so glad you were able to locate the 'power supply loss' so quickly! 'Best to you',

rig

You are a true asset to this forum. :hello:

 

[rigtec]

You are a true asset to this forum. :hello:

Right back at-cha Halko! :hello: ...and thanks for those kind words!

Greg

 

[Ray Dunakin]

These threads are really valuable. If any of this kind of stuff happens while I'm in the middle of nowhere, at least I'll have some idea of what to do.

 

[Hltoppr]

Just an update:

So this issue reared it's head again...same thing; gauges dropping out and ABS, traction control, etc. lights coming on...this time upon every depression of the brake pedal.

I took it to my local dealership (who are awesome, by the way), and had them take a stab at diagnosis.

There's a tech who's a Toyota and Lexus electrical guru, who found that a ground was faulting on the ABS CAN when the pedal was pushed. Checked the ABS ground pins and found they were all secure. Tech decided to add an additional spliced in ground for the ABS CAN and the problem resolved.

If anyone has this issue in the future, PM me and I'll put you in touch with the folks who diagnosed the issue...I'm sure it'll pop up on other 5th Gens.

-H-

 

[Hltoppr]

Yet another update.

Issue came back, in minor form...ABS, Multi-terrain select blinking and "traction control system unavailable"

Dealer is replacing the skid control ecu....

We'll see if this works out the issue.

-H-

 

[Hltoppr]

Finally figured this thing out...after the ABS pump/ecu was replaced...it was reading codes for a fault in the unit.

After replacement, the issue came back again.

Have to hand it to the awesome tech at Findlay Toyota in Flagstaff, Arizona who took the time to drive around with me for an hour until we replicated the intermittent issue.

Turns out there are 2 brake switches on the brake pedal; one just turns the brake lights on when the pedal is depressed. The other is essentially a brake pedal position sensor switch, which reads to the ABS, VSC, A-Track and Traction Control ECUs...basically every bell and whistle that's attached for traction control of any kind.

This switch is located vertically behind the brake pedal itself. Apparently, a loose pin fit, when the wiring vibrated (and gravity, I suppose) caused all sorts of intermittent ground faults; essentially causing the dash to light up like a Land Rover.

Field fix was to zip tie the lower wiring so that it was tight; not allowing the pins to fall with vibration or gravity. A new wiring harness was installed, and no more issues.

Odd placement for something that could cause so many issues. I may make a guard for it, just so it doesn't get kicked or knocked.

A picture of the harness and connection (fixed):

Hope this helps!

-H-