DIY Cruise Control FAQ (2006-2010 Yaris)

[CTScott]

Here's a picture of one with the OEM stalk hole.

OEM Cruise Stalk Hole.jpg

[white_rice]

Can someone please tell me what the functionality is of the single OEM wire/pin that plugs into the D3 connector on the steering column? I ask because I need to replace this connector but want to know what I'll be unhooking exactly, once removed.

Thanks.

[CTScott]

Originally Posted by white_rice

Can someone please tell me what the functionality is of the single OEM wire/pin that plugs into the D3 connector on the steering column? I ask because I need to replace this connector but want to know what I'll be unhooking exactly, once removed.

Thanks.

The black wire is for the horn.

[SKurj]

Ok so my steering wheel cover came in today. I followed all the steps, and kept saying to myself.. too good to be true... too good to be true....

Everything back together, start the car.. airbag light won't turn off... uh oh here we go, what did i break or do I need to run some wire to some pin...

Pop the airbag off again, and notice I hadn't pushed the yellow clips back in. Didn't figure that could be it, but put it back together and started it again. The light went off!!

Too good to be true... Too good to be true...

Test drive time, I notice the cruise indicator on the dash works, good sign. The damn cruise does everything its supposed to flawlessly.. for less than $100... and 30 minutes labor..

Makes no sense toyota doesn't offer this cruise..

Many thanks to Scott for this!

And in this case it's everything its claimed to be.


P.S. If anyone wants the stock steering wheel cover without hole cut, just cover shipping and its yours (note I am in Toronto Area).

[burdenj]

Hi everyone, first substantial post here!

Thanks to this awesome community, my 08' Hatchback now has cruise as well, just put the finishing touches on it this morning.

Please forgive the dirt, it's only just barely spring in St. John's, Newfoundland. Also, that mess that looks vaguely like a circuit is all tidy and covered in heat shrink now

For the switches, I used double throw momentary toggles which are off at the centered position. I know it doesn't look stock like some of the push button switches do, but I just have a thing for toggle switches.

I got them from Digikey if anyone's interested (450-1530-ND).

[Brianr4]

Finally finished installing all of mine and it works perfect!
I think it works better then the factory cc in my Tundra.

Have to give much thanks to CTScott for making the kit...selling the kit...and for being so patient with all my questions!

His brain must be super huge!!!!

[Saggio]

Installed my kit today from Scott. LOVE it!

Thanks again!!!

[Brianr4]

Scott, did the horn plug make it back to you?

[CTScott]

Originally Posted by bobor

Hi everybody,

I own my small Yaris and like the car very much. The only minor thing I miss is the CC feature. Since the european models do not have support for CC built in ECU and I do not want to invest too much money in some aftermarket model, so I decided to build my own one.
The idea is very simple. I would like to use a microcontroller to periodically check all necessary input data (current speed, brake & clutch pedal positions, etc.) and then set the digital2analog converter to emulate the accelerator pedal movement by increasing / decreasing the output voltages on both lines to ECU as the speed of the vehicle is under / over set value.
I currently have an open question related to accelerator pedal connection. There are 6 wires for 2 separate Hall probes to detect the pedal position. Of each set, one wire is +5V, second one is GND and the third one is the output, where voltage changes according to accelerator pedal depression level. I would like to cut these two signal lines and put them as input to CC module and connect another two wires (output from CC) as input to ECU. So far so fine.
But my idea is, that during the time CC is switched off, the signal input and output are directly interconnected and when CC is enabled, the output is fed from DAC. I would like to use a relay controlled by microcontroller for this purpose (see fig.). but I am not sure, if it is a good idea. What is your opinion. Is there any better solution for this?
If I use the relay, will there be any problem with temporary loss of signal to ECU during relay switching (the actual switching time is approx. 5 ms)? Or shall I add some small capacitor between output & ground to smooth the glitches. But I have no idea what capacity to use in order not to influence the response time of accelerator pedal too much.
And finally, do you know about any place where can I get at least accelerator pedal connectors (male & female) or the whole accelerator interface harness from ?
I appreciate any ideas. Thanks

With the amount of development required to safely implement cruise control, I would think that in the end run it will be less expensive to use an aftermarket cruise control system. I realize that the primary aftermarket system available in Europe is very expensive (~$700 US), but I believe that the Rostra aftermarket cruise control system, which is sold in the US and Canada for ~$200 US, will work on the European Yaris.

[CTScott]

Originally Posted by bobor

Hi CTScott,
thanks for your response. I admit its time consuming process and there are many risks to consider, but it's my hobby At the moment I would say I have 90% of the source code ready, so there are only minor modifications to be done and a lot of testing and bug fixing But except my free time I invest into it, the parts will cost me not more than 20 EUR ( ~30USD).
Regarding the aftermarket models, the situation is slightly better than you expect, at least here in Slovakia. I can get one for ~450 USD, but still Rostra model even including shipping costs would be cheaper. And I don't see any reason why it should not work on European models.

But as I said, it's a hobby.

OK. In that case, back to your original question - I would not use mechanical relays. I would stick with solid state switching, by transistor or FET, to avoid the switching delays.

[CTScott]

Originally Posted by bobor

Unfortunatelly I do not have any experience with solid state switching. If you could point me to some good tutorial, I would appreciate it But AFAIK in this case, the input signal (voltage level) from either accelerator pedal (hall probes) or DAC would be somehow degradated (lowered) due to voltage drop PN junction.
Solid state switching is definitely faster than mechanical relay. But advantage of a relay is that it does not require power supply to interconnect one of the input lines to the ouput. I though of using this a safety mechanism, so in case anything goes wrong I would just switch off the power supply to cruise control module and the relay would (almost immediatelly) switch back to default state (direct connection of accelerator pedal). But if I find some good solution using solid state, I am about to change my mind.

Here's a pretty good intro to transistor switching.

http://www.kpsec.freeuk.com/trancirc.htm


Rather than switching back and forth, it may actually make more sense to put the microcontroller in between the pedal and the ECM. That way, the ECM samples the pedal outputs and then in normal mode, just emulates what it sees. Then, in CC mode it ignores the input and sends its own output.

The other advantage of this method is that you can improve the throttle response in normal mode (like the Blitz throttle controller does).

[CTScott]

Originally Posted by bobor

Thanks for the link, I will have a look on it. Your idea seems quite interesting, maybe I will change my plans a little bit and implement it that way. But I still have a feeling, that switching between DAC and pedal accelerator outputs is a little bit more safer.

Another idea came to my mind how to avoid switching delays with a relay. If I connect the DAC output directly to output line of the relay (to ECM) and accelerator pedal to one input of the relay (the second input remains unused), I can first set the output voltage on DAC and then switch the relay (cut the accelerator pedal line). On a switch back, the accelerator pedal is switched on first and then DAC disabled. This way, there is no voltage drop on signal line to ECM.

The only drawback is, that all time, when DAC is not in use (even just before switching off the accelerator pedal line, when DAC output is set) there is voltage from accelerator pedal to DAC output. I have no idea, if it can harm it in any way and what the impedance between DAC output and ground. If the impedance is too low, it can make a short connection and damage the ECM, that I obviously would like to avoid

And finally, do you have any idea, what size the input impedance of ECM could be?

The impedance on the ECM input pins is approximately 2K Ohms.

[49erRider]

Couldn't get mine to work and tried searching these posts but has anyone else had an "a ha" moment when theirs didn't work and want to share?

[CTScott]

Originally Posted by 49erRider

Couldn't get mine to work and tried searching these posts but has anyone else had an "a ha" moment when theirs didn't work and want to share?

The most common one with 06-08's, when using the OEM stalk is not properly seating the ECM pin. The check for that is to measure the voltage on the wire connected to the ECM pin with the ignition switch in the on position (engine not running). It should measure 12 Volts with no buttons pressed on the stalk. If it does not, then the pin is not seated properly or is in the wrong location.

[49erRider]

I figured it out! I had 12volts to the ECM pin so that wasn't the problem. When I drive I ride with my foot just resting on the clutch. That was enough to remove pressure from the plunger causing it to not activate.

Works great, another thankful yaris owner Scott!

[hayden]

Hey CTSCott - if you remember I bought a CC stalk from you along with the wiring kit. It worked fine for a month or two and you may remember me posting that it stopped working occasionally and would also sometimes make the car accelerate on it's own.

It eventually stopped working entirely but just now had time to go out with a multimeter to test it. This was done about a foot of wire away from the computer thingy (on the firewall in the engine bay) at one of those snap-close connectors I used. The ignition was on (I know you told me to do it with the ignition off, but hopefully this works too) but the engine off.

Car on but engine off: 12.3v
With the on/off button held: 0.2v
Held down: 6.1v
Held up: 3.4v
Held toward: 8.6v

Any idea why the CC wouldn't be working AT ALL? I have no idea what these values are supposed to be. I'm concerned that maybe the wire thickness I used may be too much, but I have no idea how these things work. I think it was the same type that you used in the wiring kit (had to buy extra from radio shack).

Thanks a ton for your help!

[CTScott]

Originally Posted by hayden

Hey CTSCott - if you remember I bought a CC stalk from you along with the wiring kit. It worked fine for a month or two and you may remember me posting that it stopped working occasionally and would also sometimes make the car accelerate on it's own.

It eventually stopped working entirely but just now had time to go out with a multimeter to test it. This was done about a foot of wire away from the computer thingy (on the firewall in the engine bay) at one of those snap-close connectors I used. The ignition was on (I know you told me to do it with the ignition off, but hopefully this works too) but the engine off.

Car on but engine off: 12.3v
With the on/off button held: 0.2v
Held down: 6.1v
Held up: 3.4v
Held toward: 8.6v

Any idea why the CC wouldn't be working AT ALL? I have no idea what these values are supposed to be. I'm concerned that maybe the wire thickness I used may be too much, but I have no idea how these things work. I think it was the same type that you used in the wiring kit (had to buy extra from radio shack).

Thanks a ton for your help!

Those voltages are fine (and that is correct to measure them with the engine off, but ignition on).

Try wiggling the ECM Pin while measuring to make sure that the connection is not intermittent.

Can you refresh my memory on if you have an AT or MT?

[hayden]

It's an AT 2007 2 door.

If there was no connection at all to the ECM, would that line still be powered? I'll go reseat the pin and see if that helps because it was definitely intermittent before dying entirely.