Wish I had cruise control...

I don't think criuse control can be added to the Prius.

 

The ECU on the Prius has cruise control built in, just as all Prius have the EV feature, but in the U.S. we don't get the EV button to use it. Your cruise control is there, but you have no way to turn it on or control it. You need the wiring harness and the control stalk. I don't imagine they are installed on the basic model, otherwise it would have cruise control. It might be possible to add, but it doesn't sound easy.

Tom

 

I suggest you ask your dealer whether a cruise control kit is available. Basically, the cruise control kit would include the switch that mounts to the steering wheel, the brake light switch, maybe a new steering wheel, and maybe a new wiring harness.

The hybrid vehicle ECU has a pin that controls the cruise control function. The cruise control switch applies various resistances across the pin to provide instructions to the HV ECU regarding OFF, ON, SET, RESUME, and CANCEL.

In the "old days", owners of Classic Prius that were not factory-equipped with cruise control could retrofit this to their vehicles.

Good luck.

 

Hmmph! Didn't know it was an option (or absence) that you could get or strike.

 

I find myself using the CC less and less as I drive my Prius, I want to 'control' the vehicle, do pulse-and-glide, use mileage maximizing techniques which I happen (probably erroneously, but I have my ego to consider!) to think I am better at than some computer-chip. I did use the CC on a long trip, primarily to reduce fatigue, but don't consider myself a CC driver at all. None of the three Toyota pickups I've owned over the years, including my current base-model Tacoma, have had CC and I've never felt that it was a major handicap.

 

I believe that 2008 was the first year where cruise control was made optional on the non-Touring Prius, to help keep the base price down. You have to buy option pkg #1 or better to get CC.

Touring comes with option pkg #1 at minimum, hence CC is a standard feature of that model.

 

It can be done. I have retrofitted CC in my Classic. The Italian '04 Prius also do not have CC. Some owners bought the CC kit from France.

Here is the Part List for your reference.

 

hmmm so how much is 102 euro's?:croc:

 

Around 16,000 yen.

 

I note in other threads, some have been able to get parts to add OEM Cruise Control in Japan and Europe, but I have come to a suspician that the Cruise Control might be tied in with the Vehicle Stability Control System for US Prius.

Refernce attached Cruise Control Schematic for connections to:
Throttle Control Motor, see page 261
Engine Control Module, see page 261, 262
Hybrid Vehicle Control ECU, page 263 thru 269
Multi Function Display a.k.a Combination Meter, page 263
Body ECU, page 264
Skid Control ECU, Power Source ECU, Gateway ECU page 265
Stop Light Swith (on brake pedal), page 266
Shift Lever Position Sensor, page 267
Cruise Control Switch, page 268
Motor Generator 1, page 268
Motor Generator 2, page 269
View attachment CruiseControlCircuits.pdf

I assume the majority of the components above are already in place besides the Cruise Control Switch and Skid Control ECU, but the software could also be different. Also, the lamp for the Cruise On dash indicator might not be populated.

I can hardly believe they would leave off cruise control if it was only a matter of the switch.

Note that the Cruise Control Switch uses short cicuit and three different resistances to send signals for On/Off, Resume, Set and Cancel functions with two wires Connector C12 under the steering column.

If someone without Cruise Control wants to conduct an experiment to determine if all components are in place, remove lower cover from steering column and find connector C12 with two wires Red and Green not connected to anything, see attached drawing.
View attachment Dash Harness.pdf

This would go to the Cruise Control Switch if you had one. The system would be turned on by a direct short (no resistance in the Cruise Control Switch) applied between these two wires with HSD on. If the Cruise Dash Light comes on, I would run out to a dealer and buy the Cruise Control Switch.

Another option might be to buy a universal after market cruise control and rig the mechanical solenoid to the accelerator pedal under the dash. Due to cramped space, probably would need to devise some sort of pully arrangement with no chance of binding.

 

Thanks for providing the .pdf wiring diagram. I believe that the brake light switch also has to be added. So, to augment the experiment that you suggest above, the switch has to be simulated by providing 12VDC to terminal ST1- when cruise control is desired, and then simultaneously opening the connection to ST1- and providing 12VDC to terminal STP to simulate pressing on the brake pedal and disengaging cruise control.

The universal alternative seems dangerous and cumbersome to attempt.

 

Are you talking about SW 16 Stop Light Switch on page 266? That is one component I would be shocked if it is not already in place on all Prius. Even the most basic models have Brake Lights on the rear, and this is the switch that operates them.

I'll retract my suggestion that a solenoid from an aftermarket Cruse Control might be fit uder the dash to operate the pedal. I looked it over and you are right, there is realy no place to rig anything like that.

 

You may be right... It depends upon whether the Prius w/o CC has a SW 16 that contains two switches or not. If that model has a SW 16 that only has one switch, then a new switch would have to be installed.

The reason I am thinking this might be possible is because on the early Classic Prius that did not have cruise control, it was necessary to install a brake light switch as part of the retrofit. Since my documentation is for the earlier 2G models, I don't know how the 2008 w/o CC is wired...

 

The Spanish MSN Prius user group has a long discussion about adding cruise control to a 2004 Prius. Apparently their cars came equipped with the single brake light switch. Cars with cruise control have a double brake light switch. Anyway, several of them succeeded in adding cruise control by adding the cc switch, a new cover panel, a new cable, and the changed brake light switch. Finding a dealer who could do the work covered most of the 8 pages of comments. One guy used the rather colorful phrase "when frogs grow hair" to describe his dealer's service. So the parts are easy, the knowledgeable installation has something to do with frogs growing hair... Maybe it was just Google's machine translation, but the context seemed very similar to "snowball's chance in hell"...

 

Find a currency converter like we have to all the time and punch it in. :fear:

 

Perhaps the parts may be available from a wrecking or salvage yard?

 

Roughly $160 at today's exchange rates.

 

The Stop Light Switch S16 is different on a CC-equipped Prius. As RobH has pointed out, it is a double switch instead of single. The white color switch on the left has 4 contacts whereas the black color switch on the right has only 2.

S16 1-2 is normally open and 3-4 is normally short. When the brake pedal is pressed, 1-2 will be shorted and 3-4 will be opened at the same time. When HV Control ECU sense the absent of 12V at ST1-, it will cancel CC.

I retrofitted my Classic from the instructions found here:

Cruise

As for the Stop Light Switch, I used a normally closed Relay to connect S16 3-4. When the brake pedal is pressed, 1-2 will be shorted and this would trigger the Relay to open 3-4. It works like a charm. I've been using this for 4 yrs without problem.