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Discussion Starter #1
Hey guys,

So i got a 2012 Honda odyssey. After purchasing, bought a vcm muzzler. After a few months, got tired of the eco light coming on almost constantly when stuck in traffic. So, i ordered an s-vcm to keep that from happening.

However, this is our work van which sees A LOT of startups every day during service calls. So, the s-vcm was installed correctly (checked with s-vcm company as well). Now, it will work okay most days. Then, if its a hot day outside, it will work okay. One random startup, and the eco light will come up all the time while driving. Shut off and start up on the next service call, no eco light. Say i'm idling a lot in traffic, and then shut off. Come back out, start up and eco light comes on again every time i'm coasting or cruising.

Sometimes, i noticed if i'm on the highway and it cools off, eco lights off again.

I checked the coolant temp with scan tool as per s-vcm company request, its showing me 74 fahrenheit. I checked this on different days. Same reading. I also removed the battery connection and cleaned and re-installed. No change.

I emailed them, and they sent me a replacement s-vcm unit. I installed it. And the eco light came on again today (installed 2 days ago). Contacted them again. I bought one for my pilot too, it SEEMS ok, but it doesn't see multiple startups like this and rarely gets driven.

I'm stumped. Is something wrong with my van?

Any suggestions?

I'm literally about to pull out my hair lol. I'm sick of seeing that stupid green light come on! I want 6 cylinders, ALL THE TIME!
I was about to dump money and buy a vcm-tuner next, but i don't want to if theres something wrong with my van. I figure if the ect sensor is bad, it would throw a cel.

Thanks
 

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Coolant temp reading 74 degrees?? You got a real problem there lol even if it's at 174F VCM will activate. It has to be below 167F for VCM not to activate.
 

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I checked the coolant temp with scan tool as per s-vcm company request, its showing me 74 fahrenheit. I checked this on different days. Same reading.
Assuming you mean 74*C? (=165*F) Even when the ECO light turns on? That's an odd one.

My guess is that your van has a bad cooling fan or similar and the SVCM is bypassing for 'over-temperature' reasons. You'll need to check what the ECU is reporting for coolant temperature when the ECO light is illuminating. You may find it is 205*F+ (96*C+).

-Charlie
 

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Discussion Starter #9
Sorry guys, typo indeed. I made sure the van showed the eco light one day, and it was indeed 74 degrees celsius on my scan tool.

It is very strange as its intermittent. Some days, no eco light. Other days, eco light.

And i notice its only when outside temperature is above say, 25-26 degrees celsius. The weather was showing constantly closer to 30 celsius last week and the eco light was on, A LOT.

Today, 23 degrees celsius steady. No eco light all day.

What could i check? I checked the cooling fans by turning on my a/c. They are working. Is there another check to make sure they are actually coming on under normal conditions? I dont use my a/c very often.
 

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Discussion Starter #10
I also made sure the connections were tight and in place. I feel if it werent, id get a cel right?

I made sure the battery connectiom was clean and tight as well.

Im going to check the coolant temp again, make sure im not just talking out my butt.
 

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I have the VCMMuzzlerII with the highest resistor, and my VCM still freaks out on 40C / 104F degree days.

We have had a handful of them this summer...
 

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I have SVCM in my van and I haven't seen a single ECO light since it was installed last fall.
Over the last few days It has seen many days of driving in 95F ambient temps.
While I don't see the eco light I do notice after a hot start the temp gauge is a little bit higher (2mm) and essentially stays there slightly higher than if it was started cold and allowed to come up to temp.

what happens if you turn off van and disconnnect the SVCM when you notice the ECO and see what temp is actually being reported.
I recall getting a CEL when I did this that I had to clear.
I'm not sure what happens if fuse is removed while van is running? Mb just the same CEL.
 

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Discussion Starter #13
Thats whats confusing me so much. Whats causing the eco light to just randomly come on.

I just let the van idle for 30 minutes. Engine fans are coming on and off.

Just checked with my scantool, coolant temp steady at 74 celsius.

Im stumped.
 

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Do you have an infrared thermometer or something that you can use to verify the coolant temperature that doesn't depend on the output of the ECT1 sensor? If the sensor is faulty, you can't hope to have a VCM disable device behave normally.
 
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Discussion Starter #15
So after idling for 30 minutes. I shut it off, started up. Went for a drive. Eco light came on.

Heres a video showing that. Very sorry for it being sideways lol. I tried to film landscape.


If i drove it around for longer on the highway, the eco light goes away.

I am going to borrow a friends scan tool to see if the coolant temp shows different.
 

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When you check temp with a scan tool and SVCM is disconnected...
If everything seems normal I would leans towards the device being defective...?
Although they already sent you a replacement right?

Is the SVCM you bought for for your pilot the exact same model ?

maybe try swapping them to see if the problem follows the device or stays with the van
 

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Discussion Starter #17
When you check temp with a scan tool and SVCM is disconnected...
If everything seems normal I would leans towards the device being defective...?
Although they already sent you a replacement right?

Is the SVCM you bought for for your pilot the exact same model ?

maybe try swapping them to see if the problem follows the device or stays with the van
Yup, this is unit #2 on the van now. Doing the same thing. My friend may lend me his scan tool tonight so i'll see whats going on. I'll try disconnecting the svcm and see what temp it shows. If the temp does go higher than normal, what could be the problem?

Thanks
 

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Discussion Starter #18
Okay, so. I borrowed my friends scan tool. Disconnected vcm and connected main harness back to ect sensor.

Temp after idling for around 30 minutes was 201.2 fahrenheit, or around 94 celsius.

Is that normal?

Connected svcm back on, temp showed 74 celsius.
 

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Yup, this is unit #2 on the van now. Doing the same thing. My friend may lend me his scan tool tonight so i'll see whats going on. I'll try disconnecting the svcm and see what temp it shows. If the temp does go higher than normal, what could be the problem?

Thanks
Why would you think a different scan tool would give a different reading? It's like looking through a broken window and realizing the window still looks broken after putting on a pair of glasses. The sensor output is the sensor output. I don't think you can keep reading the temperature using a scan tool - you need to see if possibly the sensor or wiring to it is bad, and getting a temperature reading from an instrument NOT actually connected to the van is a good start in that process.
 

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Okay, so. I borrowed my friends scan tool. Disconnected vcm and connected main harness back to ect sensor.

Temp after idling for around 30 minutes was 201.2 fahrenheit, or around 94 celsius.

Is that normal?

Connected svcm back on, temp showed 74 celsius.
It's probably not far off normal. When you warm up the engine to do an idle relearn, the engine coolant temperature needs to hit 194F (or 90C) for that process to begin. So having an idle temperature around 200F isn't unreasonable if you're just sitting still.
 
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