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2010 Forester
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173 Posts
Discussion Starter · #1 ·
FYI:
I installed a ScanGauge 2 in my '10 Forester and have been playing with the various gauges that you can monitor. One of interest was "OPEN/CLOSED LOOP". By monitoring this gauge, you can tell when the torque converter swiotches from locked to unlocked and vice-versa.

As an example, let's say the engine has warmed up to normal operating temp (~185-195 deg. F) and your coasting down the road at 40 MPH with no foot on the gas. If you check the open/closed loop gauge, it will show "OPEN" and the MPG goes to 9999 which says the injectors are turned off and the transmission is free-spinning the engine.

If you let the car continue to coast, at ~20 MPH, the open/closed loop gauge will change to "CLSD" and the MPG drops to something less than 9999. Also, if you don't touch the brake while coasting down, there's a slight nudge when the torque convert unlocks.

I also tried this in my other car, an '04 Honda Pilot, and on that one the torque converter unlocks at ~30 MPH.

This might be handy if you suspect a torque converter lockup issue in your vehicle or if you just want some feedback on how often the torque converter switches from unlocked to locked. I've read some other posts where an unlocked torque converter is the main cause of the tranny temperature rising. Note, I don't know if this works for older generation Foresters.
 

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2007 Forester Sports XT 4EAT
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Glad you're enjoying the Scangauge II! We have one in each of our 3 vehicles. As to Open or Closed Loop operation, you might want to check out this link. :wink:

From the SG2 manual:
CLSD LP/OPEN LP Fuel system loop status This indicates when the oxygen sensor is being used to control the mixture (closed-loop) and when it is not (open-loop). It is usually closed except when the engine is cold or under full throttle acceleration.

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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2010 Forester
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Discussion Starter · #3 ·
2.5x sleeper,
Yep -I'm aware of what is described in the link. My observations were taken after I had driven the Forester for ~10 miles/15 minutes (past the initial open loop stage). I monitored both the open/closed loop setting and the instant MPG and see the loop go back and forth between open and closed depending on the speed and if the accelerator is being pressed.

Have you ever played with this setting on your scangauge and do you see similar behavior?
 

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2010 Forester
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Discussion Starter · #4 ·
My understanding is that when the O2 sensors are used to calculate the air/fuel ratio in closed loop mode, then the short term fuel trims come into play. I know these can be monitored with XGAUGE on the scangauge but I don't know what I would ever use the info for. Maybe you can detect if an O2 sensor is bad?
 

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2007 Forester Sports XT 4EAT
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My main use for the Scangauge II is to monitor intake air temp, coolant temp, battery voltage & I like the digital speedometer, which is more exact & easier to read than the analog one in the instrument cluster. Of course the CEL code view & clear functions is a plus. :wink:

The SG2 uses the existing engine sensors that are tied to the ECU, so many of the functions are kinda interesting to monitor (view), but are really not of much use (for me). :smile:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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2010 Forester
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Discussion Starter · #6 ·
Yep -that's about the same conclusion I've come to. I mainly intend to use the scangauge as a trip computer. I really wish there was a way to monitor the tranny temp. I have read on some other threads that the tranny temp sensor goes to the TCU and not the ECU so it's not possible to read it from teh OBD2 port. :icon_frown:
 

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2007 Forester Sports XT 4EAT
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From my understanding & research, the Scangauge II via XGauge functions can be programed to monitor any sensor that the ECM uses. I have to admit I haven't prusued these features, but my seaching the internet found this. It's not for Subaru, but if you read the the thread, you can see the SG2 can do much more if you want to get into it. :wink:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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Discussion Starter · #8 ·
Thanks for the link. I have to dig into the XGauge programming a bit. The scangauge manual and info on Linear Logic's website are pretty cryptic. I wish they would partner more with the various auto manufacturers to reveal more of the vendor specific data that can be shown with xgauges. From the XGAUGE.PDF document, it looks like they did a lot of work with Ford and GM but that's about it.
 

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2004 Forester XT
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Resurrecting this old thread...

Has anyone with a Scangauge II and auto transmission Subaru been able to get transmission temperature readings? I don't want to buy it if it won't provide that info.

My highest priority "gauge" needs are:
Transmission Temp
Coolant Temp
Exhaust Gas Temp

I have an '04 Forester XT with auto trans.
 

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2008 LL Bean (4EAT)
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... Has anyone with a Scangauge II and auto transmission Subaru been able to get transmission temperature readings?...
Transmission temp is not listed by ScanGauge as a regular function
» Fuel Economy
» Fuel Rate
» Battery Voltage
» Coolant Temperature
» Intake Air Temperature
» Engine Speed (RPM)
» Vehicle speed (MPH and KM/H)
» Manifold Pressure (not available on some vehicles)
» Engine Load
» Throttle Position
» Ignition Timing
» Open/Closed Loop
ScanGaugeII - Digital Gauges
The SG can be programmed to look for more information, depending on the car:
You can add vehicle specific gauges to your ScanGauge.
ScanGaugeII - Add-A-Gauge
Transmission temperature is one of the functions that the SG can display, but not for a Subaru. Evidently, this information is not known to the Subaru ECU and so is not put out through the OBDII port:
http://www.scangauge.com/support/pdfs/XGAUGE.pdf
 

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2007 Forester Sports XT 4EAT
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I looked over the PDF for the Subaru select monitor & I couldn't find anything on trans temp. From what I see, the trans temp is kinda like the oil pressure light. It's off when normal & on when there's a problem. No real gauge like functions. :frown:

Curious... are you looking for one device to measure Transmission Temp, Coolant Temp & Exhaust Gas Temp? :confused:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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2007 Forester Sports XT 4EAT
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That was my goal, but it looks like it's not going to happen. For now I just ordered a ScanGauge II. I may add regular gauges (and senders) for trans temp and possibly other functions.
The SG2 is one gauge I wouldn't be without! I have one in each of my vehicles. :smile:
I monitor:
  • air intake temp
  • coolant temp (more accuate than the factory gauge)
  • battery voltage
  • digital speedometer
Most of the members that monitor the transmission temp replace the drain plug with one drilled & tapped for a standard temp sender. I still have one for sale here. :wink:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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2007 FXT vf37 swapped 4EAT w/ VDC
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I monitor instant fuel mileage, MAP, IAT, and something else on my scan gauge. The trouble code reader is also worth it.

Just because the company doesn't offer the programming to pull the transmission temp doesn't mean that the device can't read it. I might dig through their forums to see if anyone's been successful. The only problem is if you use an x-gauge then you have to reprogram all of the generic gauges. That could be a PITA.
 

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2008 LL Bean (4EAT)
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... Just because the company doesn't offer the programming to pull the transmission temp doesn't mean that the device can't read it....
The company states which ECUs know transmission temp.
The company says that the Subaru ECU does not know the transmission temp. Do you disagree with the company?
If so, why?
 

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2007 FXT vf37 swapped 4EAT w/ VDC
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783 Posts
The company states which ECUs know transmission temp.
The company says that the Subaru ECU does not know the transmission temp. Do you disagree with the company?
If so, why?
I'm not convinced that the company called up every OEM and asked them if the ECU knows transmission temperature. I'm speculating that they know the code to reach the transmission temperature for a select few types of vehicles. (betas perhaps?)

More vehicles and modes are being added regularly.
 
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