96 Ls400 Cruise Control Not Working.

[brhesson]

Bought an ls400 96 with 119k, replaced rotors, brakes, new oem shocks, hood lifters, kn air filter, poly bushings, upper control arms, motor and trans mounts, added rear sway bar, new rear trailing arms by Meagan Racing, etc. New tires.

So now my Cruise control lights up in dash as working but does not actually maintain speed aka function. Lol. Any help would be great. Not throwing any codes what so ever.

[brhesson]

Any help would be appreciated. No idea what is needed for repair. :(

[landar]

Its a tough one, Beau. I don't know enough about the cruise system to say. I would check anything that might disable the cruise, like the system thinking the brake had been pressed. Maybe a cruise controller module is bad or an electric motor or sensor is shot. I wish I knew more about the system to help but I do not. Fine Tech Guru I am ;-)

[Exhaustgases]

Its could be what ever the feed back sensor is, maybe you accidently pulled a wire or connector apart during all the work done on it.

[landar]

I am not sure about the 96, but on the 90-94 LS, there is a dash light "CRUISE MAIN". When you are driving along, switch the cruise to 'on' and try to set it. Paying careful attention to the CRUISE MAIN light on the dash, do you see it blinking at all? The earlier LS will blink the cruise light 5 times to indicate a problem. But it does not continue to blink. You only get a brief time period to see.

BTW, are you pushing up or down on the CC stalk to initially set the speed?

[brhesson]

I am not sure about the 96, but on the 90-94 LS, there is a dash light "CRUISE MAIN". When you are driving along, switch the cruise to 'on' and try to set it. Paying careful attention to the CRUISE MAIN light on the dash, do you see it blinking at all? The earlier LS will blink the cruise light 5 times to indicate a problem. But it does not continue to blink. You only get a brief time period to see.

BTW, are you pushing up or down on the CC stalk to initially set the speed?

The 96 does not flash to my knowledge. The "cruise" light comes on as normal, I typically pushed down to set, then once set could increase speed

With up push and decrease holding down. Cancel pulling towards or turn off with on/off end cap button.

Now it just never engages or sets speed. The light works normally.

I'll have to check the wires and connections. I was curious if the brake sensors on the passenger side disc brake pads had anything to do with it as I had a hard time with removing them (front and back wheels) and could not get them to stay in the new pads. So they're tied up and out of the way.

Thank you so much for your input. Both of you.

[landar]

Those are troubling words..."to my knowledge" ;-) Sounds like you are setting it correctly.

You will need to go out and try it again, armed with this new knowledge about the light, looking specifically for the brief blinking.

Also, the parking brake sensor appears to be tied into the cruise system as well and I know those things are notorious for sticking 'on'. Check your parking release lever.

[brhesson]

Those are troubling words..."to my knowledge" ;-) Sounds like you are setting it correctly.

You will need to go out and try it again, armed with this new knowledge about the light, looking specifically for the brief blinking.

Also, the parking brake sensor appears to be tied into the cruise system as well and I know those things are notorious for sticking 'on'. Check your parking release lever.

Lol, my engineer words coming out I suppose. Structures are my field of expertise. Electronics and cars I'm learning lol. Rebuilt a 3vze, 3 slow 93 4runner from the ground up, but I digress. I'll check the parking brake release also. The light doesn't blink at all. I also had very good and trusted mechanic check for codes and it's not giving any.....

[landar]

Good to hear that you are a fellow engineer. I know you will be logical and methodical. Here is what I would do:

There should be a fairly thorough treatment of the CC system and how to troubleshoot in the Lexus factory manual (I know there is in the 90-94 models). I do not have the manual for a 96, however. But you can download it pretty cheaply if you go to the Toyota TIS site and pay $15. This gives you 48 hours of unrestrained searching and downloading of all Toyota models/years including Lexus. I will warn you that you can get overloaded with all the info presented. However, if you remain focused on getting your cars info, you can download the entire manual in a couple of hours. They (Toyota TIS) do not make downloading easy. They tend to group info in small categories and you have a lot of click and saving to do but it can be done. For $15, its a good bargain.

Anyway, that is where I recommend that you start. There is a Cruise ECU, an actuator for the throttle, speed sensor, brake sensors and all that. The manual will show a troubleshooting diagram and you can maybe work thru that. Otherwise, it is a job for the shop which would have a "checker" tool they can hook up.

Finally, I suppose the problem could simply be in the CC stalk contacts and when you press down, it is not making contact. I do not know that for certain, of course, but it remains a possibility.

Here is the link to TIS -> https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti;TISESSIONID=FQNbJSYPZQ9FS9tz9n9z0CGxCTmjQVgBRFqGJGVNSLJW4Hy2GRTS!-726067647?_nfpb=true&_pageLabel=ti_faq_page

[Exhaustgases]

According to my 92 manuals, the wheel sensors are not part of it. Like landar says brake switches are part of it both park and pedal.

Always a real good check of fuse and where it plugs in, and connectors. It could be something that was disturbed working on it or maybe it just picked now to stop working from some other reason.

[brhesson]

According to my 92 manuals, the wheel sensors are not part of it. Like landar says brake switches are part of it both park and pedal.

Always a real good check of fuse and where it plugs in, and connectors. It could be something that was disturbed working on it or maybe it just picked now to stop working from some other reason.

This will be benched until likely Friday evening. But i appreciate all the input guys.

[brhesson]

I'm gonna have to look into this TSI site, owning the 93 4runner and 96 ls400 it would be awesome to be able to download so much. Might be a good idea to download some other stuff too just in case I need to swap motors in the 4runner one day. ;)

Good to hear that you are a fellow engineer. I know you will be logical and methodical. Here is what I would do:

There should be a fairly thorough treatment of the CC system and how to troubleshoot in the Lexus factory manual (I know there is in the 90-94 models). I do not have the manual for a 96, however. But you can download it pretty cheaply if you go to the Toyota TIS site and pay $15. This gives you 48 hours of unrestrained searching and downloading of all Toyota models/years including Lexus. I will warn you that you can get overloaded with all the info presented. However, if you remain focused on getting your cars info, you can download the entire manual in a couple of hours. They (Toyota TIS) do not make downloading easy. They tend to group info in small categories and you have a lot of click and saving to do but it can be done. For $15, its a good bargain.

Anyway, that is where I recommend that you start. There is a Cruise ECU, an actuator for the throttle, speed sensor, brake sensors and all that. The manual will show a troubleshooting diagram and you can maybe work thru that. Otherwise, it is a job for the shop which would have a "checker" tool they can hook up.

Finally, I suppose the problem could simply be in the CC stalk contacts and when you press down, it is not making contact. I do not know that for certain, of course, but it remains a possibility.

Here is the link to TIS -> https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti;TISESSIONID=FQNbJSYPZQ9FS9tz9n9z0CGxCTmjQVgBRFqGJGVNSLJW4Hy2GRTS!-726067647?_nfpb=true&_pageLabel=ti_faq_page