Help with sudden breaking at low speed even after the “VSC off hack” on 2000 Land Cruiser

[100Seriesforlife]

Really glad to finally join the LC community. I recently bought a 2000 Land Cruiser that I’m building into an off-road rig. So far, I’ve done the front suspension, added a lift, and serviced the wheel hubs (made sure to have the correct pre-load with final measurement of ~13 lb on both sides). I also recently got an alignment and was able to fit 35” tires.

Right before installing the 35” tires and getting the alignment, I started experiencing sudden braking at low speeds. At first, I thought it was related to the front-end work I had done and assumed the alignment would fix it.

Unfortunately, it didn’t. I then thought the issue might be due to the lift and larger tires, so I tried the VSC-off switch mod, but that didn’t help either.

I scanned the vehicle and checked live data, which showed a “0” reading from the left front wheel speed sensor at low speeds, accompanied by sudden braking and active traction control. As soon as the vehicle reaches around 19 mph, the sensor starts reading normally. I tested the ABS sensor with a multimeter, and its readings were similar to the right-side sensor.

Has anyone had a similar issue and found a solution?

Thanks

 

[2001LC]

Few thoughts:

• resistance between LF WSS and CPU. Resistance is higher on LF than RF WSS would be a clue.
• Tone ring damage.
• Wheel speed sensor damage. Some are pried out, breaking plastic. Then, may not set proper angle and or distance from tone ring.

Had you not, noted: LF not reading low speed. I'd be looking at: Did wheel hub (bearings) loosen up, R&P bushing, ball joints, TRE inner and outer, LCA bushings.



A first hit on google: (Did not VET)

https://www.carparts.com/blog/what-is-a-tone-ring-and-can-you-fix-it-in-place/

Tone ring on back of wheel hub. Is sometimes damaged from improper ponding on to remove rotor.

Sometimes seal in back of wheel hub. Is installed backward, like the one below. Metal wares and filings get on WSS and tone ring. Wheel breaing loosen fast, as metal of seal wears down

 

[100Seriesforlife]

Thank you!! I am taking the wheel hub assembly out and inspecting tone ring today (will check the abs sensor as well). is the tone ring something i can change if damage or do i have to get whole new hub assembly?

 

[2001LC]

Whole wheel hub, AFAIK!
I've a few on hand. They can be found, used.

 

[100Seriesforlife]

Will report back, might need to buy one from you if you’re selling one of them, thx!

 

[Dirt J]

Are you getting any of the wheel speed sensor codes?

Your initial diagnostics would lead me to believe the wheel speed sensor is the culprit since there are no readings at low speed.

If I'm looking at this chart right, you should get some voltage reading even at low speed:

Did the resistance of the sensors fall in the allowable ranges?

View attachment 3759282

Replacement write-up here.

I had VSC engage unexpectedly along with intermittent beeping, and the worn out steering rack was my culprit.

You said you did the VSC defeat mod, but it doesn't sound like you actually defeated it if you are still getting the unwanted/expected braking. Did it beep and flash the skidding car light when the VSC engaged? The VSC OFF light should illuminate when the defeat is engaged (I don't know if you hardwired it or installed a switch).

Also note that VSC and ATRAC are two different things. VSC brakes skidding tire above 9 mph in High, and 18 mph in Low. VSC is turned off when CDL is engaged. ATRAC (active traction control) is the "4WD assist" feature on these vehicles that also does apply braking to your wheels but in different scenarios.

 

[100Seriesforlife]

I appreciate your input! I did get the code C0205 that disappeared after i cleaned terminals last week, i ordered a sensor replacement but i am not getting that code anymore.

The resistance measurement was 0.95 for the left which was also the same on the right.

I did the hardwire mod for vsc, and i do have the vsc off light on.

Will replace the sensor and check on the hub assembly, hopefully its the sensor because i don't wanna deal with broken tone ring

 

[2001LC]

Right "before" installing the 35” tires "experiencing" sudden braking at low speeds.
so I tried the VSC-off switch mod, but that didn’t help either. Again issue was before!

I scanned the vehicle and checked live data, which showed a “0” reading from the left front wheel speed sensor at low speeds,

Signal from WSS, indicates wheel not turning.

around 19 mph, the sensor starts reading normally. I tested the ABS sensor with a multimeter, and its readings were similar to the right-side sensor.

19 MPH could be a clue. As to where resistance issue is, if issue electrical as opsosed to mechanical.

 

[100Seriesforlife]

So could still be bad sensor, right? I guess will see when i change it

 

[2001LC]

Sure. multimeter test can fool us. Easy to enough, toss in another WSS (wheel speed sensor. AKA: ABS sensor), see what happens.
You can also look at tone ring through WSS port, while it's out. Using a borescope, would give a clear view as you spin wheel.

 

[Dirt J]

Any update on this?

 

[100Seriesforlife]

Any update on this?

So i inspected and cleaned my tone ring but that didn't help. I finally installed a new ABS sensor on the left and that fixed it so far. Hasn’t been doing the weird breaking at all since.