Odd cruise problem

[cjsupra90]

Has anyone ever had this problem and or know what could be wrong?

Here it is. Anytime that I go to turn the cruise control on after the car has been off, it wont turn on right away. It can take anywhere from 30sec. to 10 min. for the light to come on on the dash. once it turns on the first time then I can shut it off and turn it back on and there is only about a 30sec delay until I shut the Ign. off, then it does the same thing again with the first time turning it on and taking for ever to come on.

Playing with the button does not help either. There are no codes and once the light comes on, the cruise work perfect.

Any ideas anyone?

 

[mrnickleye]

Is there a relay?? I'm not gonna check the tsrm for you. But....maybe if there is one, the current flow to/thru it is bad, and it takes a while to operate.

Vacuum to the cruise control tank??

 

[cjsupra90]

There is a relay and that is what I was thinking sort of cause they are not like your standard normal relay in the way that they operate. Haven't checked it yet, was planing on doing that today.

Deffinitly not a vacuum problem. Its that the computer is not turning on right away. So my guess is either computer or relay.

 

[cjsupra90]

When you say the light on the dash I assume you're refering to the light in the switch.

According to my Toyota Cruise Control Service Manual the CC switch for the type of CC system used in the Supra is not just a simple switch. It has a relay integral to it. That relay is powered by an electronic circuit inside the switch that controls the CC system whenever it's powered off by the ignition. This is so the CC doesn't come back on (if left on) when the ignition key is cycled.

The schematic shows the switch's indicator light to be powered by this circuit and not by the CC computer. There are also no inputs back to the switch from the computer. What does all that mean? It implies the problem has to be within the switch itself. You may want to run the CC diagnostics just for grins but if nothing comes up I'd change the switch.

No, I am refering to the green LED light in the dash in the Speedo head unit to be more exact that tells you when the CC system is turned on. There is no light in the switch or no relay. There is a seperate power relay under the dash next to the CC computer, but it tests fine. I am pretty sure that it is the computer itself now after checking everthing according to the TSRM today. Everything check out fine, but the TSRM says nothing about a delayed power up. I even took apart the computer and checked everthing in there, but nothing seemed to be wrong. So next thing is to find a known good computer and try it.

I would like to see what schematic you are looking at. From what I have seen, there is nothing like that.

 

[Jeff Lange]

Jetjock, 89+ Supras have the cruise indicator on the dash, and a relay added under the dash, as the on/off switch was changed to a monetary type on the steering wheel. It is the typical cruise setup used by Toyota starting in the early 90's.

My guess is the problem is probably the cruise main relay.

 

[cjsupra90]

Jet: Yeah sorry about that. I guess that it would have helped if I said that it was a 90 model year, and Jeffs pictured shows it in the tach not the speedo my mind wasnt thinking straigt when I typed that before.

 

[Cup_of_suprA]

Put the car on jack stands and test the cruise...

 

[cjsupra90]

Jet, yeah the relay works perfect. So the only thing that I can come up with is the CPU itself. The thing that bogles my mine is why does it actually come one after a short while. Its like its waiting for something like an input signal from something, but all the signals are working plus there are not code to begin with and at the same time non of the signals should keep it from powering up. Plus, once it does finally come on, ths CCS works perfect.

 

[cjsupra90]

Put the car on jack stands and test the cruise...

The system works perfect once it turns on. The problem like I stated earlier is that when you turn the switch on, the system does not turn on right away and the delay actually varies anywhere from 30sec. to 10 min. before it finally turns on.