Add Cruise Control to 2015 Prius c one?

Yes i Have a Prius c 2. I think the cruise control is very important on the Prius. I use mine all the time. I find its one of the best gas savers next to the Eco button which use all the time.

 

I agree, particularly after I acquired a new-to-me 2001 Prius which, thankfully, had cruise installed.

On a 2001-2003, and perhaps on others, the "drive by wire" accelerator pedal is really a rather complex electronic encoder, and which on some models, certainly including 2001-2003, is prone to early wear-out. The replacement, if available at all, is very expensive.

On 2001s, cruise was not available, although many added it later. By 2003, it certainly appeared to be an available option as the 2003 electrical wiring manual covers this "accessory".

The basic cruise control is unchanged from 2001 (and perhaps 1997) on to the present day: it is a simple device which has four normally-open switches connecting resistors to an external voltage source, with one end being connected to the ECU (which provides a 12 volt source), and with the other end being connected to ground. Only two wires!

The values of the resistors are chosen so that these electrical potentials will be presented to the ECU, each potential representing a different functional command to the ECU: 12 volts (no switches selected), 9 volts, 6 volts, 3 volts, and, I suppose, zero volts.

The wiring diagram for a 2003 Prius is identical in the cruise control area as a 2014 Prius c One. And by strong inference, identical in my 2001.

So, having cruise control on an early Prius is essential, and potentially saves the very high cost of replacement of the accelerator pedal encoder.

The advantage of constant speed driving is obvious.

On my 2001 (which is on its second traction battery, but everything else of any major significance is original) are 250,000 miles, with the traction battery having been replaced at 150,000 miles.

I use cruise on my 2001 and my 2012 LB Two all the time.

I have yet to install the cruise kit on my 2014 c One.

 

Cruise control is a nice luxury, if you use it. The reality is that it is very hard to use it on California freeways as there is just too much traffic and stop and go driving. As soon as I engage cruise control, its time to slow down or stop.

 

It works well in suburban and rural California, but certainly much less so in urban California.

 

I'd assume OEM cruise control would be easy, I doubt Toyota uses a different ECU for the non cruise ones. In my 2008 yaris all I did was buy a stick a few wires and pins. The stalk even had perfect mount points in the steering wheel, then it was just a matter of running a few wires.

 

Correct ... the ECU already has the software in it to perform the several algorithms which are associated with the cruise control function.

Basically, the ECU monitors the voltage across the CC switch which is arranged as a multi-position voltage divider. A change in voltage is analyzed and a software function which corresponds to the change in voltage is performed.

So ... you install the CC switch (which has the resistors built in), and the wire to the ECU (which supplies a voltage reference, about 12 volts) and the wire to ground (which supplies the ground reference, obviously zero volts), and you are done.

Its just that the that the two wires go to two completely different locations within the vehicle, and the switch is difficult to install, requiring partial disassembly of the steering wheel, and the mechanical modification of a snap-in escutcheon [ * ] .

Conceptually very simple in design ... conceptually very complicated in implementation.

[ * ] See Escutcheon | Definition of escutcheon by Merriam-Webster, definition 2.

 

mmm-hmm.

 

I hope I'm always able to keep and maintain a vehicle that has cruise control.

I guess I've become spoiled, but I wouldn't want a vehicle without one.

UNFORTUNATELY, in the past 2 years I've gotten a few speeding tickets, and the cruise control is the greatest safety feature in terms of helping me make sure I don't accidentally get another. I really NEED to be able to set the speed, and know I'm not accidentally drifting higher than the posted.

Is cruise control a luxury?
Yeah, I'd have to say YES, because I've owned so many vehicles in the past without cruise control. But it's more and more the expected norm, on nearly every level of new vehicle sold.

I think it helps promote efficiency, and safety, and I've become so spoiled having it, not only with the Prius but the last 3 vehicles I've owned, that NOT having it at this point would feel like a real loss.

 

Unfortunately, CC is a computer algorithm which is an integral part of the ECU.

And, as such, the computer-based CC algorithm is subject to "overshoot" and "undershoot" which is unavoidable. This is necessary for control system stability.

This means, for instance, that climbing a hill may (and probably will) result in 1 MPH higher when the top of the hill has been reached.

This also means, for instance, that descending a hill may (and probably will) result in 1 MPH lower when the bottom of the hill has been reached.

This effect is a consequence of the control system "dead band" which is essential to make (almost) any control system algorithm "stable". For, should the algorithm be "unstable" it may "hunt" about its "set point".

I have tested the CC in my 2001 (same switch and wiring as on my 2014 c, and presumably on my 2012 HB, and probably the same algorithm, too) over many days and temperature conditions and the behavior is always the same: a 1 MPH overshoot or undershoot at the expected times.

Should the posted speed limit be, for example, 65 MPH, just set your level CC speed at 60 MPH, and you will be guaranteed of maintaining 59 to 61 MPH irrespective of the terrain conditions.

 

I know the Cruise Control may not be "exactly perfect" at all times based on terrain and driving conditions. But my experience with all cruise control I've had is that they have been accurate and consistent enough that if I set it to the local speed limit it's going to keep me close enough that I think my risk of getting a ticket, even if it should go a MPH or two above is minimal to non-existent.

The truth is today, most of the time if YOU are going the speed limit, nearly everyone around you is going 5-10 or maybe even more MPH above it, so a 1-2 mph deviation is not a problem.

The only time of course I cannot rely on cruise control is when going directly down a very long or steep incline. Where I have to take the responsibility to brake to maintain the speed.

I don't expect "perfection" from cruise control. And I'm OK with that. I learned to drive without it, I still know how to drive without it.

 

I want to try and do this. But I require adult supervision when around tools. Does anyone have a link on Amazon or eBay to the exact kit I need to buy???

 

Current eBay item number 222820920613 is a "complete" Prius c (and others) cruise control kit, which includes no extras (as on the Rostra kit).

Included are:

1) cruise control switch unit with the ground wire already removed,

2) two screws to mount the switch to the steering wheel,

3) short wire for ground connection (includes proprietary connector on one end and a ring on the other end, to be connected to frame ground; from wheel connector, pin 1),

4) long wire for ECU connection (includes proprietary connectors on both ends, and is nylon mesh reinforced, to be connected to ECU connector, pin 28; from wheel connector, pin 2).

Best of all, this kit is complete and costs just UNDER FIFTEEN DOLLARS (and shipping is free).

 

Just ordered it!!! Thanks!!! Is there a video tutorial on how to install it???

 

Alas, there is no YouTube video for the Prius c One ... the present YouTube video is a generic one, and applies to many Toyotas, but not to the Prius c One.

The instructions for installation on a Prius c are downloadable at http://www.thecruisecontrolstore.com/250-1836-toyota-prius-c-complete-cruise-control-kit-2012-2017/ and are stated to apply to Prius c Ones from 2012 to 2017.

Do bear in mind that the early Rostra kits included an extra wire which was required to be removed prior to switch installation. The later Rostra kits may not include that superfluous wire, while the non-Rostra kits, including the one which I identified, above, do not include that wire.

The concept is quite simple: the two wires from the switch are brought to a connector within the steering wheel, and the switch and these wires rotate as the steering wheel rotates. These two wires reappear on another connector within the non-rotating portion of the steering column; from the non-rotating connector, one wire (the short one) is brought from wheel connector G5 pin 2 to frame ground, and the other wire (the long one) is brought from wheel connector G5 pin 1 to the ECU connector G58, pin 22.

It may be confusing, but the G5 pins are counted from the bottom left, whereas the G58 pins are counted from the top right.