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@e320 - What are your cooling fans doing during all of this?
 

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Discussion Starter #22
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.

Wanted to double check with a different scan tool to make sure mine wasnt being weird as its an older one.

I do have an infrared thermometer, but what would i be pointing it at. The engine? Would this give me an accurate reading similar to coolant temp?

I just find it very strange that the eco light is still coming on, at random. Even if it was giving a faulty reading, the svcm's job is to show 74 celsius to prevent it from coming on. Even though the svcm is showing 74 and sending that signal forward, why do i still get a random eco light. And if the eco light does come on, its not like its only for a split second or 10 seconds, it stays on for the rest of the drive. What does that mean? A loose connection would lead me to think id see random flickers of the eco light, rather than it being constantly on for the rest of the drive, when it does randomly show up.

If there was something wrong with the ect sensor, id get a check engine light.

That only leaves something wrong with the svcm device, or something wrong with my vehicles battery maybe?

Im honestly stumped but am open to suggestions as i refuse to give up on this
 

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Discussion Starter #23
@e320 - What are your cooling fans doing during all of this?
I checked those out yesterday while i let the van idle, they would cut in and out from time to time.

If i turn on my ac, they stay on...as they should.
 
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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.
Sounds normal.

AC off, fans come on 'low' at 195*F and 'high' at 205*F
AC on (compressor engaged), fans will be on 'low' at all times and 'high' at 195*F

Both fans should operate the same (so, one never is on without the other).

-Charlie
 

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Even though the svcm is showing 74 and sending that signal forward, why do i still get a random eco light. And if the eco light does come on, its not like its only for a split second or 10 seconds, it stays on for the rest of the drive. What does that mean?
Whoa, what? So, the light never turns off again for the rest of the drive?

The ECO light should only come on while cruising at a constant speed under light loads (not going up a hill) or coasting. It should be off when stopped or accelerating. There is also a delay between getting to a constant speed or coasting and the ECO light turning on (like 2-5 seconds, depending).

-Charlie
 

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Discussion Starter #26
Whoa, what? So, the light never turns off again for the rest of the drive?

The ECO light should only come on while cruising at a constant speed under light loads (not going up a hill) or coasting. It should be off when stopped or accelerating. There is also a delay between getting to a constant speed or coasting and the ECO light turning on (like 2-5 seconds, depending).

-Charlie

Sorry, i should have elaborated. By "staying on" , i meant it stays on when coasting or at constant speed, it does go off when accelerating or idling.

Im just used to it "being off" with the svcm lol
 

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Sorry, i should have elaborated. By "staying on" , i meant it stays on when coasting or at constant speed, it does go off when accelerating or idling.

Im just used to it "being off" with the svcm lol
exact same issue I have with VCMuzzlerII on HOT 40C/105F days.

I am not having the issue from frequent start up and shut down like you, but its worse from city driving.
 

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Discussion Starter #28
exact same issue I have with VCMuzzlerII on HOT 40C/105F days.

I am not having the issue from frequent start up and shut down like you, but its worse from city driving.
Yup. Thats exactly why i switched from the muzzler 2 to the svcm, because it advertised that it keeps the eco light off always.

And after reading forum posts, thats what it does.

Wonder whats wrong with my van lol
 

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I believe thermostats are supposed to or typically fail open but maybe the van thermostat is sticking slightly?

Can you try leaving the scanner connected and drive with SVCM on as well what does the coolant read when the eco light comes on during driving not just idling. Sorry if you already did this.
 
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Discussion Starter #30
I believe thermostats are supposed to or typically fail open but maybe the van thermostat is sticking slightly?

Can you try leaving the scanner connected and drive with SVCM on as well what does the coolant read when the eco light comes on during driving not just idling. Sorry if you already did this.

Nope havent done this yet. But ill give it a go and report back
 

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Discussion Starter #31
So, eco light was gone all day today with a mix of city and highway driving. Got back into town and had to make a pitstop. Started it up, and the green light of death came back.

So, hooked up my scan tool, and it reads 74 celsius with svcm hooked up. But why is the eco light coming on with this temp reading?

I have no idea.
 

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If you are driving with scanner connected what is the range?
For example I just took a long highway trip and my scanner showed anywhere from 161F to 166F depending if I was sitting in traffic or coasting down a long hill.
It won't hurt anything to drive with it connected

Question when you say it came on did you then stop van( eco light goes off turn) then check temp at it says 74 or is that 74 shown reported as you coasting with the eco light actually on?
 

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If you are driving with scanner connected what is the range?
That's a datalog there in the picture. 74*C, flat line. Right where it should be, so the SVCM is working exactly as designed.

I have no idea why the ECO light would still come on though!

-Charlie
 

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Just a theory, but I think you have a sketchy engine coolant temperature sensor.
Heat buildup when the car is turned off momentarily with the temperature spike causes the fault.

These are the voltage values out of the manual for a known good sensor.

Pink wire:
With ignition switch
ON (II): about 0.1-
4.8 V (depending on
engine coolant
temperature)

It would be nice to know what voltage you get at what temperature.

Would also be good to know if this problem is more prevalent on really hot days with AC roaring vs cooler days.

this one has everyone stumped.
 

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Discussion Starter #35
Just a theory, but I think you have a sketchy engine coolant temperature sensor.
Heat buildup when the car is turned off momentarily with the temperature spike causes the fault.

These are the voltage values out of the manual for a known good sensor.

With ignition switch
ON (II): about 0.1-
4.8 V (depending on
engine coolant
temperature)

It would be nice to know what voltage you get at what temperature.

Would also be good to know if this problem is more prevalent on really hot days with AC roaring vs cooler days.

this one has everyone stumped.

Thanks for the reply. I guess voltage would be checked with svcm disconnected and ignition on? Or would i plug in the normal vehicle harness and check with that plugged in?

I was kind of considering a fault temp sensor too as the stuff im experiencing is really odd! I might just buy a new one and swap it out just to see what happens if the voltage measurement shows good.

Yes, the eco light coming on is definitely more prevalent when its hotter outside, and/or lots of stop and go traffic. But i HAVE to shut the engine off, and on again to make the light come on, for example. If it hasnt been coming on for the current drive im on, it will stay off, no matter if i idle for an hour, or am stuck in stop and go traffic. But if i say, while stuck in that same traffic for a while for example, shut off my engine and restart immediately, boom eco light will start coming on.

I dont use my ac often, but i did occasionally use it on my 3 hr highway drive today. Got off the highway into town. In town driving (w/o) ac for about 15 min. Not much traffic. Got to my service call. Came back out 10 min later, started er up to drive home and voila, eco light cycling on/off for the rest of the drive.
 

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Thanks for the reply. I guess voltage would be checked with svcm disconnected and ignition on? Or would i plug in the normal vehicle harness and check with that plugged in?

I was kind of considering a fault temp sensor too as the stuff im experiencing is really odd! I might just buy a new one and swap it out just to see what happens if the voltage measurement shows good.

Yes, the eco light coming on is definitely more prevalent when its hotter outside, and/or lots of stop and go traffic. But i HAVE to shut the engine off, and on again to make the light come on, for example. If it hasnt been coming on for the current drive im on, it will stay off, no matter if i idle for an hour, or am stuck in stop and go traffic. But if i say, while stuck in that same traffic for a while for example, shut off my engine and restart immediately, boom eco light will start coming on.

I dont use my ac often, but i did occasionally use it on my 3 hr highway drive today. Got off the highway into town. In town driving (w/o) ac for about 15 min. Not much traffic. Got to my service call. Came back out 10 min later, started er up to drive home and voila, eco light cycling on/off for the rest of the drive.
Looks like when there is a temp spike from the engine being off, and no coolant flow across the rad to dissipate the heat.
these vans aren't equipped with fans that run after the key is off to bring those temps down, like many turbo vehicles do.

I was out today, and the VCM was panicking again in city traffic. No AC at all (rarely use it) and about 32C / 92F degrees

if your scan tool provides the ability to run the cooling fans, maybe that could be a test when you shut it off momentarily.

I have conceded that this might be one of those things you cant be OCD about, and just be happy that garbage gimmick is off and not destroying the motor 90% of the time.
 

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Just curious...how many miles does your van have? You may have multiple potential issues just from age ( sensors, wiring, missing software updates). Perhaps check Honda Tech Bulletins?
 

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Discussion Starter #38
Just curious...how many miles does your van have? You may have multiple potential issues just from age ( sensors, wiring, missing software updates). Perhaps check Honda Tech Bulletins?

My van has 219,000 kms or about 136k miles.

Just purchased it used maybe less than 6 months ago at the local honda dealer. It was a trade in, as is where is deal. Had a side impact history.

One owner vehicle with every maintenance record at this honda dealer.
 

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Discussion Starter #39
Looks like when there is a temp spike from the engine being off, and no coolant flow across the rad to dissipate the heat.
these vans aren't equipped with fans that run after the key is off to bring those temps down, like many turbo vehicles do.

I was out today, and the VCM was panicking again in city traffic. No AC at all (rarely use it) and about 32C / 92F degrees

if your scan tool provides the ability to run the cooling fans, maybe that could be a test when you shut it off momentarily.

I have conceded that this might be one of those things you cant be OCD about, and just be happy that garbage gimmick is off and not destroying the motor 90% of the time.
Yeah i purchased the svcm specifically to make sure the eco light doesnt come on at all.

But if i dont find a solution, i guess ill just be living with it. Its off most of the time, thats all that matters i guess. But im really curious whats causing it to come on randomly even when the svcm is reporting the 74 celsius like it should.
 

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Yeah i purchased the svcm specifically to make sure the eco light doesnt come on at all.

But if i dont find a solution, i guess ill just be living with it. Its off most of the time, thats all that matters i guess. But im really curious whats causing it to come on randomly even when the svcm is reporting the 74 celsius like it should.
If you have the scanner connected continuously while driving it is a flat line at 74F?
I just took a 1000 miles trip and I saw fluctuations from 161 to 166F coolant temp while driving on highway up and down mountains with SVCM connected.
 
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