Abraham Bonet

On my 99 Toyota Tacoma 4x4 3.4 the 4wd deceleration sensor is missing, sometimes i put on the brakes and I get a very heavy vibration on the petal and it will not stop. Lucky I had space to pull over and push it to park. The abs light always on.

wyoming9

iTrader: (1)

Well if your ABS light is on it means you have a failure in the ABS system!!

If your brakes don`t stop the vehicle that should confirm you have a problem.

If your not skilled enough yet maybe get your Brakes looked at!!!!

Brake pedal pulse is often warped rotors

When was the last brake inspection ?? What do the Pads measure ??

How are the Rear shoes are you keeping them adjusted using the emergency brake ??

Just what is this 4wd deceleration sensor ??
Is it a automatic Transmission part Having never learned to drive a Auto Trans let alone seen one I Have no clue.

Malcolm99

The speed sensors are the usual culprit of ABS light and ABS disabled. My guess is one of the 8 pistons on the front calipers seized and warped your rotor, so you will want an inspection done by a professional from the sounds of your description. Very rare to have a problem with the decel sensor for 1998 - 2004 models and they run $1000 each

MudHippy

Sure sounds like normal ABS function to me. That's how you know it's working.

1. You feel the pulsation in the brake pedal as the ABS system kicks in, applying and releasing the brakes in rapid succession, to avoid wheel lockup.

2. So you can verify the pulsation isn't an issue with the brakes the ABS light comes on. Letting you know all is well. It's just the ABS working.

3. The unintended side effect of ABS is on certain very slippery surfaces the vehicle can't stop. The ABS is too sensitive in detecting wheel slippage. But it has to be. Or it wouldn't work, when it works. Basically ABS is great when it actually helps you safely come to a stop, but totally sucks when it prevents you from coming to a safe stop. It does both very efficiently. Depending on the circumstances.

If you start down a slippery slope in a vehicle with ABS...you're going to the bottom...whether you like it or not. Maybe you can get slowed down enough to throw it in park somewhere along the way...if you're lucky. I guess the e-brake might help with that...if you can remember to pull it in time. If not...enjoy the sled ride!

Malcolm99

The ABS light doesn't light up when ABS is working or activated, if the ABS light is on there is a Fault in the system, Code reader should tell him which speed sensor is at fault. Sounds like his braking systems has been neglected causing pulsations due to a warped rotor due to a seized caliper piston. ABS simply doesn't work if the light is on. Note he would also hear the ABS system buzz when activated which is not possible with the ABS dummy light on. His main concern is the decel sensor which as far as I know does very little and rarely becomes a problem, now if it is missing from under the steering wheel that will disable the system aswell obviously. Some times metal can build up on the ABS Magnet causing an ABS malfunction.

MudHippy

Oh...did Toyota overlook that too? Why am I not surprised?

So you can't visually confirm when, or if, the ABS is working during operation then? That's super intelligent! That's such a "no duh, of course you need that" type of thing, I figured it was prevalent in all modern vehicles. I guess not. I almost can't believe it. Do you realize how much safer it is to know the ABS is being activated? I've had it(the "Low Trac" ABS indicator light in my 98 GM) come on without being able to detect it any other way. Let me know I hit black ice I couldn't detect either.

And no, any Toyota equipped with ABS is off my menu permanently(esp. now that I know it's inherently flawed). Don't own one now, nor will I ever. They quit making quality vehicles well before then anyway. I'm not an idiot.

Terrys87

iTrader: (1)

I have an 01 runner and had to deal with warped rotors. Having them turned solved the problem temporarily but actually in a very short time makes the problem worse. The rotors just heat up that much faster and warp again in my opinion.

A friend of mine had me to switch to a certain rotor and ceramic pads and no further issue and can get that information if you want. It will be a day or two before I see him. Warped rotors is a common problem on these generation of trucks.