ScanGauge II - Product Review

Phase one of the test was to install ScanGauge in a Ford E150, driven from Philadelphia to Wisconsin and back. The E150 is an 8-passenger van (pictured below), suitable for hauling a large group of people with a lot of luggage (in my case, combining a vacation with a college student move-out).

With ScanGuage II on the E150, we were able to average 16.4 mpg on the 1,600 mile trip. The lowest mileage segment of the journey was 14.9, over the mountains for a few hours.

Job one, on receiving the device, was to plug the "male" end of the connector plug on the cable into the Onboard Computer Display (OBCD) receptacle, which on most modern vehicles is located just beneath the dashboard, near the steering column (as pictured below for the E150).

Note: if you decide you might want to get a ScanGauge II, it would be a good idea to locate the OBCD port on your car beforehand.

The entire mounting process took perhaps 10 minutes, and would have been closer to 2 minutes if not for the repositioning I did to get it "just right."

Job two was to dash-mount the ScanGauge display with a bit of sticky-backed velcro that came with it. I found that it is very important to place the device carefully: where the view of other instruments is not obstructed, and where the steering wheel is not blocking the driver's view of the mileage display on the device. If you can't easily see it you won't get the feedback.

Instantaneous readout, it turns out, is a big part of the human interface magic (more about that below).

Mounting on the dash took a few minutes, and a bit of trial and error. Lucky for me I had some extra sticky-backed velcro in the house, as I found that I had to reposition it several times to find just the right placement.

What does it do?
It seems that many people lack a native understanding that "mileage" is an average of some very low and some very high, as well as "typical" efficiencies over the course of a drive. ScanGauge makes the reality of mileage variation painfully obvious to even the least mechanically minded driver.

Teens in the van were initially shocked that stepping on the gas after a stop light turns green, or on an uphill course of highway, leads to instantaneous mileage in the 3 to 5 range. Accelerating slowly...painfully slowly if you are a teen I would imagine...raises instantaneous mileage to the 8 to 10 range. This simple information feedback was a big attention-getter. Hopefully, the doors to efficiency understanding were permanently opened.

That said, a still more powerful feature of ScanGauge is the ability to average mileage by preceding hour(s), days, and weeks. Taking turns driving on our cross country trip, I was able to demonstrate at our rest stops, with hard numbers, who the most efficient drivers were and who the least efficient drivers were. Let us just say there were some grimaces and no argument about the costs and benefits of cautious, slow acceleration.

I calculated partway through our first, 760 mile leg of the journey, that ScanGauge saved us an hypothetical $35, based on the presumption that it would normalize everyones' driving to the best hourly performance observed. This convinced me that if the gift of feedback is accepted among all drivers of a vehicle, that the $150 device can pay itself back in a reasonable time frame.

Further Utility
After the road trip, and well after the novelty factor wore off, I moved ScanGauge into the Scion Xa favored by the teen drivers in our family. After each trip out, I "polled" ScanGauge by pushing a button two or three times to see the average mileage for preceding hour and had, then, an objective, though unpopular, discussion about driving habits and gas cost/environmental impact.

Note to self: probably not a good idea to try this with my wife.

Learn To Talk Like A Mechanic
Car dealer service agents have explained to me that they use a similar scanning device as a routine part of performance diagnosis, as a part of emissions testing, and, when needed, to teach a complaining car customer how to drive in a manner that obtains the mileage advertised on the showroom sticker!

Using the advanced features of ScanGauge II, I was able to calm my concerns about a potentially needed expensive repair. [Non-gearhead alert. Reading the remainder of this post may cause mental anguish if you don't get into technical car stuff.]

About a year ago my Toyota Corolla went into the shop with the "Check Engine" light on. The service agent said that the fuel injectors were plugged and that, before replacing them at several hundred dollars a pop, he suggested cleaning the injectors. I authorized that; and, all seemed well for awhile.

Months later the engine seemed rough. I added a can of fuel injector cleaning solvent to the fuel tank, thinking that might help. At the time I did this, I remembered how the first cars with fuel injectors in the USA (early 1980's) often needed this treatment every year and that, after the treatment was added to the fuel, that I would take the car out on the highway, drop it into a lower gear and rev it up, which resulted in a black cloud of exhaust for a few minutes, as all the crap was freed up from the fuel lines and burned.

A week or so after the fuel treatment, my Corolla's "Check Engine" light once again came on. I put ScanGauge to work, scanning the computer for error codes or set point violations. Up came Code P0420 on the ScanGauge screen. I Googled that code, and found out it meant that the exhaust stream oxygen sensors, up and downstream of the catalytic converter, were giving similar readings, indicating that either the converter had failed ( $1,500 replacement part), that the oxygen sensor(s) were malfunctioning, or that an engine failure was causing contamination of the catalyst. I was hoping, of course, that it was the latter: that, in fact, I had caused the contamination, temporarily, by freeing contamination from the fuel lines and injectors. I used ScanGauge to purge the code from the onboard computer, which in seconds turned off the light.

Final Chapter
A few days later on a high speed drive to the airport, with the Corolla engine running hot, the "Check Engine" light once again turned on. When I returned home, I again used ScanGauge to purge the code and guess what? It stayed off!

Warning. You can't use ScanGauge to beat the emissions test requirements. Your mechanic will know that you have purged any codes if you bring the car in right after you use a scanning device to remove a code from car computer memory. The OBC polls the various engine parts at preset intervals; and any real issues will eventually be detected. Only if the problem is transient, as with my temporary self caused contamination of the catalytic converter, can you really "intervene". The real utility of ScanGauge, then, is to better inform yourself about potential problems and not have to take the dealers word as the only source of information.

TerraPass lists ScanGauge II on their product page, which is here.

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