Cruise Control?

[Boomyal]

This is for a '91 Previa RWD. The cruise control quit. It appears to be a failed servo. The system will momentarily engage, then with a slight bang, it will slip out and release the throttle. You can re-engage it and it will do the same thing. Try it a few times and the CC indicator light starts flashing until you turn off the CC.

I guess the Servo is up under the dash. Is there anything that is remotely serviceable in the servo? In typical modern fashion with all this electronic wizardry, Toyota wants about $1500 for a new servo. Even though my '91 only has 139k on it, that has to be near what it is worth.

Toyota is very proud of their parts. They wanted something like $1400 for a new catalytic converter,( a metal ring came loose inside and sounded like a bucket of bolts) $1500 or so for a new cable assy for the big sunroof, (motor runs but roof does not move. Maybe opened the sunroof 24 times before it quit) and now, $1500 for a new CC servo. These are parts prices only. No labor included. I guess they must expect you to run the vehicles into the ground, junk it, then go buy a new one?

[timsrv]

Make sure the reservoir for the brake master cylinder is filled to the "full" mark. If it's near the "low" mark, fluid can slosh around and cause the low brake fluid switch to randomly send a signal. The cruise system is tied into the brake system & if a fault (such as low brake fluid) is detected, it will shut off. This may not be your issue, but it's a quick and easy thing to check and it's often the culprit. Tim

[Boomyal]

Make sure the reservoir for the brake master cylinder is filled to the "full" mark. If it's near the "low" mark, fluid can slosh around and cause the low brake fluid switch to randomly send a signal. The cruise system is tied into the brake system & if a fault (such as low brake fluid) is detected, it will shut off. This may not be your issue, but it's a quick and easy thing to check and it's often the culprit. Tim

Hmmmm! I'll check it. Wouldn't that be something?

[kiowa]

Make sure the reservoir for the brake master cylinder is filled to the "full" mark. If it's near the "low" mark, fluid can slosh around and cause the low brake fluid switch to randomly send a signal. The cruise system is tied into the brake system & if a fault (such as low brake fluid) is detected, it will shut off. This may not be your issue, but it's a quick and easy thing to check and it's often the culprit. Tim
I'll agree with Tim. My problem was that the hand brake was not working as it should. It was clicking, when engaging, more than it should i.e. when pulled it went thru' 9-10 clicks, and shouldn't go more than 7?. Can't say that the number of clicks are correct, but you get the message.

[Boomyal]

Hmmmm! I'll check it. Wouldn't that be something?

Well unfortunately that was not it. Also as I got to thinking about it if low brake fluid would disable the system it would just act as if it were turned off. It would not give the sharp 'slipping off' sound that occurs when the servo tries to grab and control the throttle.

So I think I am back to the 'defective servo' theory.

Interesting to note, the cruise control section of the factory manual is about 1/2 inch thick. No simple system, this cruise control is.

[timsrv]

it if low brake fluid would disable the system it would just act as if it were turned off. It would not give the sharp 'slipping off' sound that occurs when the servo tries to grab and control the throttle.

Actually it would. When you're marginally low on fluid it will alloy you to set the cruise, but any sloshing of the brake fluid will cause it to sharply & suddenly release. Anything that makes your brake light in the cluster come on will do the same thing. But it sounds like your issue is something else. If you end up needing to experiment by replacing parts, look for one of these in a salvage yard. All Previas had cruise control, and there are lots & lots of them in the yards right now. I'm sure you can find a good $1,500 servo for around $30. Other parts will be priced similarly and you'll get the benefit of learning how to remove before tackling your good Previa. Tim

Looks like there's even a Previa here at the Vancouver Pick-n-Pull http://www.picknpull.com/check_inventory.aspx?Address=98674&Lat=45.925618&Lng=-122.698569&Make=Toyota&Model=Previa&Distance=50

[Boomyal]

Thanks for that link, Tim. Next time we have a sunny day, I'll head on over there. The last sunny day I spent replacing the front brakes on my Wife's Lincoln LS.

[schultzee]

Where is the REAR brake reservoir located? I found the main brake reservoir under the front hood and it was full. But can't locate the rear to see if the low level might be causing my issues.

[timsrv]

Same reservoir for front and back. Front/back are divided at the master.

[schultzee]

Well I guess it's not my brake fluid level then.

Besides the module near the gas pedal, are there some vacuum hoses I can easily check that might be broken?

[timsrv]

Check to insure the e-brake is completely in it's rest position. Tim