New user (with Cruise Control Issues)

Joined
Jan 5, 2022
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6
Location
Western Australia
I have an 80 series Sahara with a faulty CC. I'm on this site as when I googled "80 series cruise control issues" this site came up. I've read through a few of the posts on the topic but none of them addressed the particular problem I have.

Firstly it's a 94 model with 1HDT motor that I believe to be a Jap import (to Australia). Consequently it's not a real Sahara as it doesn't have factory diff locks, but it has refrigerated centre console, climate control, and cruise control.

The problem with the CC is that it works intyermittently. At slow speeds it works fine, but not at highhway speeds. Suppose I set it at 100kmh. It might hold that speed for a couple of minutes, and then the speed will suddenly start falling, down to say 85kmh. Then it will begin violent acceleration (as though I;ve floored it) up to say 110. Then it backs off, speed falls down to below 100, then it accelerates violently again, and so on. After 2 or 3 cycles of this the CC just disconnects completely.

I've been to Toyota several times, and so far have had several components replaced. They now tell me it's the speed sensor. But there's two problems with this. Firstly, surely if it was a faulty component it just wouldn't work at all, not work intermittently. Second problem is that this part is no longer avail;able.

It seems to me that the problem is that there is a bad connection or dirty component somewhere. My impression of the Toyota dealership is that they're only guessing, as 80s with factory CC are very rare here.

Does anyone here have any idea what the problem may be, or who may know?

Thanks in advance
 
Joined
Nov 17, 2021
Messages
1,265
Location
Arlington, Wa
I have an 80 series Sahara with a faulty CC. I'm on this site as when I googled "80 series cruise control issues" this site came up. I've read through a few of the posts on the topic but none of them addressed the particular problem I have.

Firstly it's a 94 model with 1HDT motor that I believe to be a Jap import (to Australia). Consequently it's not a real Sahara as it doesn't have factory diff locks, but it has refrigerated centre console, climate control, and cruise control.

The problem with the CC is that it works intyermittently. At slow speeds it works fine, but not at highhway speeds. Suppose I set it at 100kmh. It might hold that speed for a couple of minutes, and then the speed will suddenly start falling, down to say 85kmh. Then it will begin violent acceleration (as though I;ve floored it) up to say 110. Then it backs off, speed falls down to below 100, then it accelerates violently again, and so on. After 2 or 3 cycles of this the CC just disconnects completely.

I've been to Toyota several times, and so far have had several components replaced. They now tell me it's the speed sensor. But there's two problems with this. Firstly, surely if it was a faulty component it just wouldn't work at all, not work intermittently. Second problem is that this part is no longer avail;able.

It seems to me that the problem is that there is a bad connection or dirty component somewhere. My impression of the Toyota dealership is that they're only guessing, as 80s with factory CC are very rare here.

Does anyone here have any idea what the problem may be, or who may know?

Thanks in advance


If it's a jdm import it's likely a vx limited.

The speed sensor is a hall effect sensor and most certainly can have intermittent failures.

Have you tried this?

 
Joined
Jan 5, 2022
Messages
6
Location
Western Australia
If it's a jdm import it's likely a vx limited.

The speed sensor is a hall effect sensor and most certainly can have intermittent failures.

Have you tried this?


Thanks. I haven't - I'll give that a go, once I get it reconnected. For some unknown bloody reason the dealership disconnected it last time I had it in there.

Now that I've found someone that knows something about this:

1. Where is the speed sensor and what does it look like?
2. Do you have any idea where I can get a 2hnd one? I figure there must be one somewhere in in the world.
 
Joined
Nov 17, 2021
Messages
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Location
Arlington, Wa
Thanks. I haven't - I'll give that a go, once I get it reconnected. For some unknown bloody reason the dealership disconnected it last time I had it in there.

Now that I've found someone that knows something about this:

1. Where is the speed sensor and what does it look like?
2. Do you have any idea where I can get a 2hnd one? I figure there must be one somewhere in in the world.

Vss #2 on the t-case

 
Joined
Jan 5, 2022
Messages
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Location
Western Australia
Vss #2 on the t-case

I’m sorry I don’t understand. Presumably you mean the transfer case. What is vss #2? Also, what does it look like? I have no idea what I’m looking for. Thanks.
 
Joined
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Messages
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Location
Arlington, Wa
I’m sorry I don’t understand. Presumably you mean the transfer case. What is vss #2? Also, what does it look like? I have no idea what I’m looking for. Thanks.

I have a 91. My setup is completely different. The images there show the approximate location of the sensor.

From my reading there are 2 vehicle speed sensors or vss.
 
Joined
Jan 5, 2022
Messages
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Location
Western Australia
I have a 91. My setup is completely different. The images there show the approximate location of the sensor.

From my reading there are 2 vehicle speed sensors or vss.
I'm sorry, images where? I can't see any images.

And there are TWO speed sensors? Why? If one measures speed what's the other one measuring?
 
Joined
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Messages
6
Location
Western Australia
Joined
Jan 5, 2022
Messages
6
Location
Western Australia
If it's a jdm import it's likely a vx limited.

The speed sensor is a hall effect sensor and most certainly can have intermittent failures.

Have you tried this?


I've refreshed my understanding of the Hall Effect (I'm actually a scientist, although my main area is chemistry) and I can't see how an intermittent fault is possible. Actually I'd say the opposite - that type of sensor is utterly impervious to an intermittent fault - it's a non-contact device that relies upon an induced electric field. But if there's something I'm missing please enlighten me
 
Joined
Nov 17, 2021
Messages
1,265
Location
Arlington, Wa
I've refreshed my understanding of the Hall Effect (I'm actually a scientist, although my main area is chemistry) and I can't see how an intermittent fault is possible. Actually I'd say the opposite - that type of sensor is utterly impervious to an intermittent fault - it's a non-contact device that relies upon an induced electric field. But if there's something I'm missing please enlighten me

As a technician, I work with a variety of sensors.

This sensor is designed to detect a magnetic field, and as such any corrosion, dirt, or variance in conductivity between the field and the sensor can cause a failure.

Also to add. Bad wiring can cause an intermittent short in the sensor pulling the signal to ground.
 

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