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Discussion Starter #1
I'm snapped a bunch of pictures today when I did my VCM disable project on our 2005 Odyssey EX-L. MANY, many thanks to kgardonia, verbatim, thenaaks, etc....all the the users that actually figured this out. I take no credit for figuring it out...I just wanted to show what I did (with pictures) to disable VCM on my 2005. If you are interested in disabling it on the newer 2008-on models, you can buy a nice pre-made piece from the user verbatim that is literally plug and play. If I had a newer van, I would 100% would have gone that route.


Here's what you need:

-Male and female terminal disconnect's. I prefer the "fully insulated" ones that have plastic covering the entire connector
-1/4" heatshrink
-some 16awg wire
-83(ish) ohm's worth of high quality metal film 1% tolerance resistors. 0.5watt or 1watt. I used 1 watt, which is overkill, but they're good resistors. I bought mine from the user communications_lab on eBay. Great seller.
-red butt connectors (the smallest ones)

-IMPORTANT: You need some way to monitor actual engine temperature from the OBDII. I used a ScanGaugeII, because I already have one. I would recommend getting one, but if you get it JUST for this...it's makes the project a bit pricey. They are very useful overall....and if you fancy yourself a do-it-yourself car guy....you should have one. :)


Pictures of the stuff:







1) Drive the van with your OBDII monitoring tool hooked up, and watch the temp gauge and the OBDII reported coolant temperature. You'll notice on a test drive that your ECO light won't come on until the coolant passes 170(ish). This is the entire premise of this fix: make the ECU think that the engine isn't warm enough to engage VCM.

Here's my van, fully warm, before the disable wiring





2) Pop the hood and let it cool off a bit while you head to the workbench and make your wiring.

3) Using butt connectors, connect your resistors and your terminal disconnects. Since the resistors have small stiff wires on them, I didn't trim them at all for the butt connectors..just passed them all the way through. More metal to crimp, better connection. I added a length of 16 AWG wire because the terminal/butt connector/resistor combo is long and stiff and I didn't want to have to bend it at all when it was installed. The wire gives you a nice flexible section to get it arranged when you actually install it. Use heatshrink before you put that last terminal disconnect on. Also, I forgot to put the terminal connectors on in a way that would allow me to take the wiring out, and plug the factory wire straight back together....now if I take mine out, I'm left with two female ends. Oops. I won't ever be taking it out. ;)




Finished product



4) Unplug all three connectors that are the same wiring harness trunk, to give you plenty of room to work.








Continued in next post......
 

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Discussion Starter #2 (Edited)
5) Strip the sheath and tape from the coolent sensor wiring.






6) Cut one of the wires, I chose red. I don't think it matters. Then crimp your terminal disconnects on, and plug in your new wiring.








Plug everything back in, and you're done.

I didn't disconnect the battery (something I normally do, and you probably should).....which might have led to me having a CEL when I first started it after installing the resistors. I got P0113 and P0118. Those are coolant and intake temp sensor voltage errors. After turning the van off, and clearing the codes, they stayed off.

Went for the big test drive, and......drumroll..........no VCM. Also, no ECO light, not even once. Granted this is just one test drive, that lasted 15 minutes of highway and around town. Here's what my temp gauge looked like:



But the ScanGuageII told the real story. Cruising down the interstate, I was sitting at 166. Stopped at a stop light for a while, it went up to 172. But when moving it stayed around 166.



 

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Discussion Starter #3
In case there is any confusion, THIS is the temp sensor, and the one you need to cut and install your wiring on:





Finally, I used a good amount of di-electic grease in the terminal connections, since they are exposed. You also don't HAVE to use two resistors...I just couldn't find any rated for 83 or 84 ohms....so I combined the 82 and the 1.5.
 

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Awesome DIY. Thanks.

So this can't be done without a temp monitor?
 

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Discussion Starter #6
Awesome DIY. Thanks.

So this can't be done without a temp monitor?
It can. But. You run the risk of not knowing exactly what you've done.....so if for some reason your wiring was bad, etc....your engine could be running at 145 degrees....and you might not know. The temp gauge on the dash simply isn't accurate enough.


You could definitely do it, and then take the extra step to check your temperatures if you notice something is obviously wrong.
 

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Great post, thanks. The temp gauge before and after looks like it didn't even move. Is that what it shows with the resister in?
 

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Discussion Starter #8
Excellent!

What happens if you simply disconnect this sensor? Just curious.
You'd get a CEL and the engine wouldn't get to temp properly. Depending on how the ECU saw it, it may even put the engine in limp mode. I'm not sure, because i haven't tried it. :)
 

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Discussion Starter #9
Great post, thanks. The temp gauge before and after looks like it didn't even move. Is that what it shows with the resister in?

Yep. The temp gauge on the dash really didn't change at all. If I didn't have the ScanGauge, it would seem the engine was the same temperature. And honestly...it might be! The actual coolant temp may very well be the exact same, but this one sensor is just giving a tweaked reading. That would be absolute best case scenario.
 

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Discussion Starter #11
So quick question. Since you have a few extra resistors/ connectors, care to build and sell me one? ;)
haha, I thought about that. I've got enough resistors to make 7 more. I'll see if I can put another one together tomorrow, and I'll pm you.


Also, I drove the van more tonight, and the OBDII reported temp hung out at 164-166. The temp gauge on the dash went to it's normal spot. The VCM never engaged, and the ECO light never so much as blinked. Which makes me think that I'm very safely below the point that OBDII would engage VCM. I could have maybe gotten away with just using the single 82ohm resistor, since I have all that other stuff inline creating more resistance as well.
 

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Thanks for posting this! I ordered 100 ohm resistors since I live in the Phoenix area and the temps here in the summer are higher than usual. I thought I'd be able to duplicate Verbatim's harness, but I'm having trouble finding a male connector. I'll probably use your method instead.
 

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haha, I thought about that. I've got enough resistors to make 7 more. I'll see if I can put another one together tomorrow, and I'll pm you.


Also, I drove the van more tonight, and the OBDII reported temp hung out at 164-166. The temp gauge on the dash went to it's normal spot. The VCM never engaged, and the ECO light never so much as blinked. Which makes me think that I'm very safely below the point that OBDII would engage VCM. I could have maybe gotten away with just using the single 82ohm resistor, since I have all that other stuff inline creating more resistance as well.

I would be interested in in one as well. ��
 

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Thank you very much for posting this, I have already ordered some of the parts to make the same modification. I will try to put together the same setup in a few weeks and see how it goes. The 84-ish ohms seems to work but I'm curious how the 100 ohms configuration works out too. If Duke's is happy with it I may try that one first. I have a handheld scanner but I also ordered one of those Bluetooth ones you can keep plugged in so I can constantly monitor the temp using my phone. Thanks again for sharing this!
 

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I upped my resistance to 95 ohms (one 75 and two 10 ohm resistors). With temps in the mid to upper 80s outside, the coolant temps were hovering around 163-166. I did see up to 172 on a longer incline. Stop and go driving in pigeon forge only got it up to 168. Vcm kicked in a handful of times over the past 130 miles of this trip, but never for more than 30 seconds before temps went back down to less than 166. I'm thinking of upgrading to higher quality resistors to see if it'll help with the varying temps, since I'm now using cheap ceramic film resistors from radio shack with a tolerance of 5%. Though as it is, the driving experience is much nicer.
 

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I did my initial measuring on my '06 Ody with no modification yet and I got the same results. The VCM seems to start kicking in when the temp reaches ~174. The temp settled between 177-183 with the outside temp in the 70-s. I'll try to hook up a 100 ohm resistor in a week or two and see how it goes.
 

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Discussion Starter #17
It looks like Verbatim is now offering this modification with the factory style connectors for the '05-'06 vans. Unless you're really inclined to do this yourself, I'd recommend going that route. Here's a link:

http://www.odyclub.com/forums/52-2005-2010-odyssey/234113-vcm-better-way-disable.html

If you are wanting to do it yourself, you might make a couple different resistance units...I've noticed with more real world driving as the outside temps are rising, that 83.5 ohm's isn't quite enough to keep it off ALL the time. It's off 95% of the time, but I will make another one with higher resistance for the middle of the summer.
 

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Bought a 100 ohm, 1/4W resistor at Radio Shack and installed it today, so far so good on a limited drive.
I'm in the South so I think anything much lower resistance may not fool the ECM for too long.
I directly crimped a male and female connector to each end of the resisitor and the cut wire so I can take it out if needed.
Will update on mpg as I find out.
 

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I just got back from a 5000 mile 9 state road trip from NC to CO. My VCM resistance I setup was 84 ohm, 1 82ohm 1% 2 watt resistor and 1 2 ohm 2 1% 2 watt resistor in series. The majority of the trip was great, smooth driving, no issues with VCM, temps were stable, outside temp ranged from 40-80's. Going through West Virginia, VCM turned on only 2 times, as a few inclines raised the temp over the threshold, but after a few minutes, on the declines the temps stabilized and no issues with VCM. The same thing happened when I got to Colorado, as the rocky mountains put a strain on the engine during the steep inclines, raising the temp. I have ordered a connector from Maxud and Verbatim to make a more permanent installation with the option to go stock if needed. I agree with the others, if you are in warmer climate, 95+ resistance will probably be needed.

Now for new rotors and brake pads, LOL. Even though I used down shifting, D3, D2 and all, the brakes still took a beating through the rocky mountains, so I will be looking to upgrade to some better front rotors and pads.
 

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Armchair quarterback making a comment about the choice of ECT resistors...

You should aim to minimize VCM engagement as described by Logicl77, not completely eliminate it. If you suppress the temperature signal too much, the PCM may incorrectly change fuel delivery or ignition parameters when the engine is at normal real temperature. That could at least cause increased fuel consumption.

Dave
 
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