ScanGauge II Fuel Trip Computer with XGauge UK Stock

This little box is very useful. In my case it already paid for itself. I was able to clear some service codes (misfire of a cylinder). In the past I paid $69 for the mechanic to just look up and clear the code.

I really like the fact that ScanGauge displays all kinds of engine data in real time. Other devices such as the CarChip save it and then need to be connected to a computer in order to access the data.

In my opinion, the ScanGauge is worth every cent.

I have had the Scan Gauge II in my Toyota Yaris for about 3 months now, and have tested it's functionality in a wide range of city and freeway driving. Since the car is only a year old, I haven't needed to scan any trouble codes yet, so I am using the SGII primarily as a fuel economy computer.
SGII connects directly to the OBD-2 diagnostic port that is present on most vehicles sold in the US since 1996. The manufacturer, Linear Logic, publishs a list on the company website showing specifically which makes and models of cars and light trucks that the unit will and will not work in.

Features: The SGII reads the data stream from the car's engine control computer, and uses this data to calculate and display, in real time, the engine's fuel consumption, RPM, coolant temperature, throttle loading, and Trip/Tank statistics like how many miles you can go on remaining fuel, and how much $$$ worth of gas has been burned on the current trip. The unit offers something like 40 different functions and guage displays - go to the company website for a complete list.

What I like about the product: Adds fuel economy displays, plus some other guages like Water Temp and RPM, that weren't available even as options on my Toyota Yaris. The fuel economy computer feature is something that you usually see only on up-scale cars costing over $30,000 - ScanGuage II adds this functionality to almost any OBD-II complient car for only $159. The Yaris fuel guage isn't very accurate, whereas the SG-II tells me to 1/10 of a gallon how much gas I have left. At each fill-up, you can re-calibrate the SGII with the exact amount of gas pumped. This is nice because fuel density changes with the seasons as average daily temperature rise and falls, which results in changes of up to 10% in how many gallons it takes to effect a fill-up.

The SGII is pretty compact, so most owners will be able to find some place on or under the dash to mount it. At night, the display screen is backlit well enough. At night, with the backlight on, the contrast between the display background and the numbers isn't as great as I'd like, but the screen is readable enough. The backlighting is provided by a multi-color LED, and the user can select between about 16 different colors.
The display update/refresh rate is once per second (fast mode), or once per two seconds (regular mode), so the unit's RPM display may not update quickly enough for use as a real-time tachometer in a manual transmission car. However, you could certainly use it to calibrate an analog tach
Ease of use: The SGII is self-powered from the OBD-II connector, and needs no batteries. It only uses a single ethernet-type cable to connect it to the OBD-II port. One 6' cable comes with the unit, and additional cables can be purchased for $20 if you want to use your SGII in more than one car.
The SGII can be used in multiple cars, but moving the unit to a different car probably erases the "current" and "prior day" trip data.
Usefulness: This gadget is really helpful on long trips to let you know when you need to make a gas stop. In mountainous terrain, most cars use a lot more gas than when cruising on the "flats", and SGII immediately updates the tank-remaining-mileage if terrain or driving conditions change substantially. The device is sensitive enough to show even small differences in fuel economy like the difference between air conditioning on or off, headlights on or off, and tailgate up/down. The most obvious difference in fuel economy comes with changes in speed, and SGII shows in hard numbers that 75mph cruising will hurt fuel economy as much as 30% compared to keeping it under 60.
The other primary use for SGII is to scan your car's OBD-II engine control computer and display the actual trouble code when your "check engine" warning light comes on. Assuming you have a listing of the trouble codes for your car, this feature could tell you the difference between minor glitches for which repair can be delayed a few days, and major failures that need to be fixed right away. Once a fault has been repaired, SGII can be used to tell the car's OBD-II computer to reset the trouble code. I haven't used this feature myself yet, but the owner's manual describes the function well enough.

Conclusion: For $159, this is a pretty cool gadget to have in your car, especially as the price or gas is now well above $3.00 (diesel approaching $4.00/gallon in some parts of the US!). And yes, SGII works in most Diesel vehicles made after 1996 (see the list on Linear Logic's website). Highly recommended as a really useful automobile accessory that offers a LOT of "bang-for-the-buck".

UPDATE: September 2010. Have used this gadget for almost three years in my Yaris and in my Dodge diesel truck, and still functioning perfectly, despite being cooked in the hot summer sun on the dashboard several times.

One issue I have noticed when using it in the Dodge: If I run through a tank of fuel while towing a heavy trailer, then another tank of fuel while the truck is unloaded (not towing or hauling anything), the calibration changes substantially. I usually use something like "45%" for unloaded, and "25%" when towing. However, even these numbers are only rough starting points. In general, over level ground at 55mph, I expect to get 20mpg unloaded, and 14mpg towing a 7800# RV trailer. But the Scan Guage is rarely consistant, even when I am careful to set the calibration to the same numbers I calculated the last time I towed the trailer. I guess other factors like average grade, temperature, and elevation must be affecting the fuel consumption/tank return ratio of the truck's fuel injection system, and this is resulting in inconsistent reporting of fuel economy from the ScanGuage. A typical inconsistency: I drove 300 miles at 45 mph, unloaded, and the scan guage reported 35 mpg (completely unrealistic for a 3/4 ton truck, of course). Actual fuel economy was 24. So I re-calibrated, and on the next tank of fuel, the ScanGuage reported only 10 mpg when I was really getting 16 (I was towing the trailer again on this tank). This is ONLY an issue with my diesel truck, when I install the gadget in my gasoline car, it is very consistant from one tank of fuel to another, and I rarely have to change the calibration after the two fill-ups. I still like the ScanGuage and recommend it, just be aware that apparently the way it interprets fuel consumption data from the ECM in a diesel engine vehicle isn't as stable or consistant as you would get in a gasoline vehicle.

I've had the scanGuage II for about 3 weeks at the time of this review. I had bought the unit because I was interested in finding out about how my car, a 2002 Toyota Solara was holding up and what the car computer might tell me.

First the cons:
1. The cord is too long. The total run from the ODB II port to where the unit is
mounted is about a 15 inches, top. It would have been nice to have sockets
on both the plug and the SG II. Include a long and short cord, or just have it
so that cat5e network cable could be used.
Why? Because storing the excess cable somewhere is a problem, I ended up
storing in inside the panel protecting the steering column, and may have
created a short in one vehicle lighting circuits.

2. The velcro is too weak to hold the unit in place. I ended up using Radio Shack
LockTite fasteners (the clear ones) instead.
3. The manual leaves a lot to be desired, especially the pictures which are so low
contrast and dark they are useless. I had to go online and download the
manual as a PDF file.

Pros: The ScanGuage works as advertised. To me this is the Holy Grail of
advertising. It barely is worth repeating the items for sale that deliver what
they promise.

1. The display is large and very legible, even at night (or especially at night).
2. The diagnostics (both realtime and stored) are comprehensive
3. The codes are easy to read.

The biggest pro for me is being able to monitor my actual Miles Per Gallon
*mileage* I've changed my driving style from constant foot on the gas
pedal to gas-and-coast. A tank of gas lasts SO much longer now, because I
now know how much a lead foot costs. In fact for any given trip I can tell
how much it costs not only in dollars and cents, but also by engine load and
how far (or further) I got just coasting along.

The unit is (in my black & gray interior) inconspicuous, and the slightly
cheap look to the unit works to it's advantage: no one takes it seriously as
"a thing worth stealing."

If I had any indication that someone would understand what it does, I'd be
recommending it left and right. As it stands, it is something of a specialty
item, except you soon wonder how you ever got along without it.