nicely done :thumbsup:

I guess this is a home-made version of those expensive units sold online. I have been thinking of trying this for awhile(I could replicate the parking brake sensor being engaged (for dvd playback), but the speed sensor had always escaped me.) Might have to give this a try.

Since this uses a relay, couldn't you just tap into the + line coming out of the snow button to activate it (assuming the snow button acts like a normal switch, I've been looking I can't find any information on the switch in my repair docs I have from TIS)?

Now when you say a block off your location, do you mean by numbers of addresses (like your at 1400 when the gps shows 1380), or the map shows your car at an intersection a block ahead of you?

Also, about how to get into the diagnostic menu, could you do that before you made this override? This might come in handy if it works without the override. I am copying this from the 4runner site, but did you just do this:
"After the ignition switch is turned ON, check that the map is displayed before starting the diagnostic mode.
While pressing and holding the "INFO" switch, operate the parking light control switch: OFF | Turn ON | Turn OFF | Turn ON | Turn OFF | Turn ON | Turn OFF.
The diagnostic mode starts and the "System Check Mode" screen will be displayed. Service inspection starts automatically and the result will be displayed."
EDIT: tested this earlier today, it works. Will show battery voltage during operation and actual mph (which is handy as it finally confirmed what I had been thinking for awhile. The speedo on the dash reads 2-3mph fast.). I was looking for an override button like on the older version navigation dvd's, but sadly it wasn't there :headbang:

thanks!

edit: also the navigation uses the speed sensor to compensate the nav antenna when it looses signal. Like if you in a tunnel, that way you keep moving on the screen even if you have no signal, I'm sure when the override is activated that might be messed up when the nav loses signal, but when it has a signal (ie normal operation) does it mess up at all?

 

Agreed, nice write-up! :thumbsup: BTW, added to the DIY: Mods and Maintenance sticky....:chug:

 

Thanks

I think I realized the accuracy problem I'm having.

First off, the ONLY thing modded in the install was cutting the speed wire. One end goes into the circuit and the other end goes from the circuit back into the nav. This is explained in J.A.'s webpage linked at the top of my original post.

Other than that the car is "untouched". So therein lies the problem. My switch only turns the power to the circuit board on and off (the switch is on the positive wire that's tapped off the cigarette lighter thing). So while off or on, the speed wire still goes through the circuit we made which I guess just produces a bad (or no) signal when off.

What I need to do now is rewire the switch so that it establishes the direct connection of the speed wire to the nav when off.

I still want to be able to cut the power to the circuit so I will either put in a second switch or find a switch system that does both at the same time (powers the circuit and also reroutes the speed wire through the circuit).

@sweenyp: I can't seem to get into the diagnostics menu again to check the speed data being sent while the switch is off. I can get into some other menu if I hold the display button down and do the same thing with the lights though.

Today I drove 30 miles and the nav had me half way to the bahamas in the ocean so I guess it's not just a block off . Like I mentioned before, the only thing changed is the wire, so I'm going to modify it to connect directly again when the switch is off rather than always going through the circuit.

With the switch on, I have access to all features which is really nice!

I'm not sure how the snow button works, but there are like 5 wires going into it so I don't know which one to use or how.

 

for the whole speed line connecting directly to the system thing, could you use a standard auxillary relay with an 87a output? Just feed the original speed wire into the 30 pin, have a generic ground on the 86 pin, use your switch you used to activate the circuit also activate the relay on the 85 pin, then have 2 ouputs. From the 87a pin just run that straight into the headunit, then have the 87 pin run straight into the speed circuit you made. then just wire tap the output from the speed circuit onto the line going to headunit form the 87a pin. that should completly avoid the speed circuit while its not activated.

not sure if that would work with pulses, but in theory i think it would work... Though I've never used a relay for that low of power (only higher power devices (amps, headlights, etc...), so I don't know how it will respond to low power. Just a possibility

 

sweeny, that sounds like the right idea.

I just need to figure out which parts I would need. I did this without knowing much at all about electronics. I just followed J.A.'s schematic for soldering.

I'll work on that relay solution.

 

Yea this is kind of the relay I was talking about, most auto store have them (http://www.sonicelectronix.com/item...m=cpc&utm_campaign=product_ads&utm_content=pla&gclid=CJOR2ZfLyKwCFRNb7AodwAK6qA)

Just saw your update to your post
sounds like when the circuit is off, makes the car thing you traveling really fast (so navigation ignores the antenna and follows the speed sensor), so it puts you way out in the middle of no where.

As for the diagnosis menu, holding info then the lights isn't letting you in there again? Is there a different set of menu's under display? It worked first time I tried it holding info down + the light switches, then holding display for 3 seconds to close it.

As for the snow button, I'll keep looking through my files I got, i bet 2 of those are for the illumination when the headlights turn on. I'll post if I find anything.

 

I got back into the diagnostics menu and drove it around with the menu up. Apparently the switch has to be off to get into the menu.

As I drove around it actually read a constant 3mph below the dial so that's not the problem I guess.

Now I'm thinking that in my hurry to put the panels all back together I missed a connector...like the GPS antenna.

I'll take it apart again and check all the connectors on the back of the nav in a bit. I know there were two missing, but I thought that was normal. We'll see

 

Now I'm thinking that in my hurry to put the panels all back together I missed a connector...like the GPS antenna.

when I had my headunit out awhile back, I noticed not every socket had a plug, so I think that's normal.
if the antenna wasn't connected it should have thrown up an error (or seen it under diagnosis under the antenna check thing), but you never know.

good luck, its a PITA to get to the back of that thing...

 

Yeah two sockets on the back of the nav unit aren't used.

Everything was plugged in fine. I unhooked everything and plugged it back in to reboot the system again, this time outside a garage since maybe it needs to be able to find satellites at initialization. It goes through a whole loading process with progress bar etc.

Everything seems physically ok. I wonder if it's an initialization error. The last thing to try would be just connecting the wire directly again to see if that makes a difference, but there's no reason why it should.

Looking at the schematic again, the relay on the circuit actually already does exactly what i was talking about doing before. When power is off, it connects the two ends of the speed wire. When it's on, the relay then severs that connection and starts sending the pulse to the navigation unit. J.A. did a good job with the design on this thing.

Here's a picture of one of the screens of the diagnostics menu. Is this supposed to be blank like this?

 

I didn't even to bother to see if the relay installed on the board already did that...I don't know why I didn't look at the relay before posting that above haha oops.

I remember having lots of readings (coordinates, etc...) from the antenna there from earlier today...
I gotta go somewhere in the next hour and I'll look at that again and let you know.

I know you said you reset the headunit (after disconnecting the power lines to the headunit), though it appears to still be messing up. Have you thought about a full reset (pulling negative terminal off battery for awhile) to reset everything all the ECU's while the circuit is off???

 

Hmm, that's a good idea, I'll try that tonight when I go to a friend's house for dinner.

Thanks!

 

DaMaDo
I use a tool from a Mercedes I used to own to pull the center vents. You could probably make one. I had it posted here some time ago, but I cant find the post?? Anyway its a long straight piece of metal about the thickness of a coat hanger. It has a small hook on the end. I simply place it down through the vent, and hook the rear of it, down in the dash, and pull. The tool has handles on it for pulling. The vents pop right out. Plus you dont damage the dash or anything else. Ill post a pic later tonight of the actual tool.

 

Ok here are a few screens from mine.

this one below is the built in error check

yep the 1 below is full of coordinate/degrees etc, something is definitly up with your system it looks like.

I thought the above was interesting. This is when my HL is running. I saw it say battery voltage was 12.8V, I kinda freaked out thinking my battery or alternator was shot, though using my multimeter i got 13.5V from the battery terminals.... I guess this is measuring voltage at the headunit and the OEM wires going from the alternator/fuse box to the headunit are so thin they are restricting the full voltage. Only explanation for that...

anyway, hope this helps DaMaDo

 

Nov0798, Thanks, I'd appreciate that.

sweeny, thanks for those pics. Looks like you're tracking 9 satellites (the red numbers are the satellite IDs). I wonder why your GPS Information menu has navi menu on the right instead of the sensors check option like mine does. I have 10.1.

Here's what I've found so far. When I took everything apart and rebooted the system, the navigation worked perfectly. I got to my friend's house 20 miles away and all the turns etc worked out perfectly. However, the GPS Information screen was still blank. That doesn't make sense. This means my system might have always been like this and I would have never known.

Since it was working perfectly, I turned on my override and it worked perfectly, but when I turned it off, the nav didn't catch up to my new position. I had to calibrate it to where I was. Once I did, it continued to work perfectly. This is different from the first day (before I rebooted it) where it was completely erratic.

So I'm not sure if my system has ever shown satellites in the GPS info menu or if it's new.

If I never touch the switch it should continue to work perfectly, but I don't want to calibrate it every time. If it was tracking satellites like yours it would find my new position once I turned the override off.

I'm not sure what to do now. Wish I knew if it had come like this from the factory.

 

I would chalk up the different buttons as different device firmware. It could have very easily changed between '08 and '11 year models, as for the lack of satelites... i don't know, that is very strange. Hopefully someone with a 2011 can see if they have satellites listed there...

This device is essentially the same device (in principle) as those costaltech lockpicks (without a few features like parking break simulator). I'll see if I can find anything on those as to how they work, I don't see how your device could be messing it up in the long run. though I could understand the change in the speed sensor value screwing w/ the indication short-term. The system must get the signal from the antenna, realize its different from what the speed sensor is telling it, then basically shut down deeming it needs a recalibration. If those one's you can buy work, then this should, I'll see what I can find.

edit: this is a costaltech lockpick for a prius:

well I assume the purple lines are the speed line, then the 4 other ones.... 2 have to be power, but there are 2 other unknowns that come off the headunit socket. I'll see if I can figure out what those are.

you might try emailing J.A. to see if he has any more info on this

 

Thanks, I'll send him an email and see.

I have a code B15C1 in my "AVN" when I go to the failures page of my diagnostics menu. Not sure what that means.

As long as I don't go into a parking garage the nav seems to work perfectly. I just can't use the switch since it won't reallocate my new position.

 

Well I don't think the headunit is getting a speed signal at all.... are you getting a signal (in the diagnosis menu) for speed with the circuit off? the nav is suppose to work without the antenna signal because of the speed sensor. Are you sure the relay is wired/soldered correctly (pin wise)....

I looked in my docs for that error code, couldn't find anything...

 

I was looking at the pictures for the front and back of the override that I made and everything looks to be connected correctly.

I do get an accurate speed reading in the diagnostics menu with the switch to the override off.

I ordered 2 of everything since a lot of the parts are less than $1 so maybe tomorrow once I get my new soldering station I'll put a second one together and try it.

If it's the override though, it's weird that the diagnostics menu has an accurate speed with the switch off and exactly 3mph when the switch is on. I would think that indicates a properly working override, but who knows.

I'll try to grab a pic of the diagnostics code tomorrow. I wish there was a way to completely reset the navigation system. Turning off power will make it reboot and lose radio station memory, but the call history and last position stay there, so not everything is resetting.

 

i think there is a way you can clear the memory in those menu's, I think I saw that to reset it.

Sounds like the relay is working if it is picking up speed with the relay off.

 

I have a couple of question?

1. Is there any way to get in to speed signal wire than behind the navigation?
So I don't need to take the navigation out to try this.

2. The parts you listed or the circuit card you done has larger capacitor than JA had. Is any diferrence?

Yours.



JA

This is a good mod, finally somebody figure out how to do it for less than $20. :thumbsup:

 

Glad to see you made good use of the Nav Override Mod write-up!

I've read thru this thread and don't really see anything you did incorrectly. Although it is hard to tell if your board is wired up correctly from the pics, the testing you did with the switch on and off tell me that is is working as expected.

The only problem area can be that the GPS antenna connection is not making full contact. Are you sure all connections are made at the rear of the nav and that they are all fully seated?

Also, you may be interested in my newest navigation mods...Anytime Backup Camera and Video on Nav.
http://www.toyotanation.com/forum/showthread.php?t=398106

 

Well so far I've been pretty happy driving around with the switch on all the time. I never used the nav anyway since to me it was worthless if I couldn't set it while moving. I'll check the connectors in the back again. I pushed in the radio and GPS antennas in until the first resistance, but maybe it needs a second click or something.

@balot64
I'm not sure of another way to get to the speed wire. I don't know where the other end terminates. When taking out the dash panels, I noticed all the car computer boxes under there so it probably terminates into one of those which is still behind the panels.
Although the larger looking capacitor I used looks different, it's still a 1uF capacitor. The other is a 0.1uF.

@JA
J.A. Thanks again for that guide. Not only did you enable myself and others to build a functioning override, you've also enabled me to become fascinated with electronics. I just got a Hakko 888 soldering station, Arduino kit, and several electronics books. My mechanical engineering degree will require me to take an electronics engineering class along with a circuits lab so I guess this can be considered advanced preparation. I actually really enjoyed the soldering.

Hopefully I can do the new mod you posted once I'm done with my calculus II final.

One question since I haven't read about relays yet: My relay is a 5V and yours is 12V, could that make any difference in the issue I'm having since the speed wire gets routed through there when the switch is off?

 

I wasnt quite sure why you went with a 5V relay myself. But since you looked at the test screen with the switch on and off and saw the correct MPH figures (3mph with switch on and actual mph with switch off) I figured this was ok.

When you were on the test screen and confirmed the correct MPH figures, did you do this multiple times or just once? You should ensure you do this a few cycles to make sure the relay is dropping out when off and allowing the vehicle speed sensor to reach the nav screen again.

If it doesnt work after cycling the switch multiple times, then the relay can be the issue.

 

Yeah, I did it a few times. I can also always hear the relay clicking when the switch is toggled.

I guess the relay just needs 5V to activate but I'm giving it 12V which is overkill, but should work.

I just didn't know if it would alter the current of the speed wire somehow.

Since I have the parts for a second one, I might try to build one with the 12V just to be sure.

 

I thought that as well (minimum voltage needed would be 5V) but then saw the spec sheet list 9.8V as the max allowable voltage and was concerned since we are inputting 12V.

 

Good catch!, I'll resolder a new one this week.

Does this look like the right one?

 

Yes, that would work. Again, I dont really know for sure that the one you are using now is causing the issue you are having, but the one from Radio Shack is much closer to what I am running.