[Eisenson]

Refer to http://www.scangauge.com -- here are the basics:

It's a small box that fits nicely on half of the shelf created when the door below the radio is dropped, though for me that's a temporary mounting. Package includes mounting velcro, cable permanently affixed to the box ending in the OBD-2 connector, and a 24-page manual about 5"x6".

This gadget can be used on any OBD-2 car including CAN cars, and especially the '04 Prius. My son opened the box and got it installed and functional as we were driving...

When you first plug it in and hit the HOME button, the panel illuminates and you see four options: SCAN/TRIP/GAUGE/MORE. MORE leads to setup functions, including engine displacement, HYBRID setting, etc. SCAN provides error codes, if any. It also supports backlight and contrast control, provides compensation for changes in tire size,

TRIP functions go FAR beyond the Prius capability, including average speed, ET, fuel remaining, max coolant temp, max speed, and more. GAUGE permits each of four positions to be cycled through the following:

FUEL SYSTEM LOOP STATUS
INTAKE AIR TEMP
WATER TEMP
FUEL PRESSURE
GALLONS PER HOUR
ENGINE LOADING
MPG
MPH
MANIFOLD PRESSURE
RPM
THROTTLE POSITION SENSOR
BATTERY VOLTAGE

You can set up the four simultaneous readouts as you see fit, and your preferences are recorded in flash memory. Thereafter, the unit always starts with your last selection. I picked WATER TEMP, MAP, RPM, VOLTAGE but will experiment.

There's obviously no book of trouble codes for every car on the road, but many cars are covered on the net (couldn't find our Prius, regrettably).

Overall, I am very impressed. Price was $130 incl shipping from AZ, and I think this gadget pretty much eliminates the need for experimenting and building, except for fun. The electronics in the box occupy so little space that I plan to install everything behind the panel, in front of the steering wheel.

Henry

(no, I'm not involved with the company)

 

[hyperion]

Thanks Hank,
After reading all the info and printing the 25 pages of the owners manual I got my order right in.. Imagine, something aftermarket that works on the Prius. How in the world did you discover this?
I may now be able to enjoy my Prius and consider it more of a car.
I think your four choices are perfect. Coolant temp and voltage in the 12V battery are important things to know. And imagine, engine rpm!

 

[Eisenson]

I went for another nighttime drive - just to gloat!!! This is terrific.

Regarding engine rpm, I have a few comments. In my car I've installed the excellent Coastal engine-run/brake-regen indicator. It shows a red LED when the fuel pump sees power. Later, I installed a tach, but was disappointed because the system shuts down the ignition and the fuel pump power when the engine is OFF, and with the ignition OFF the RPM reads zero regardless of whether or not the engine is spinning.

Well, that's true in the OBD-2 data as well -- when the ignition is OFF it reads zero RPM regardless of whether the engine is spinning.

 

[hyperion]

When would the engine be spinning with the ignition off?
If I understand you correctly though, with the ignition (power) on, the tach indicates all engine rpm? (including spinning)
Actually this info is available and could have been viewed on the MFD if Toyota had just programed it so.
Personally, I think you have made the most informative post I've seen on this site in the past 18 months. Thanks again.

 

[RSnyder]

Methinks you guys are using two different definitions of the word "ignition".

Eisenson ignition = electric pulses going to the spark plugs to cause the fuel mixture to ignite.

hyperion ignition = the electical system that can generate these electrical pulses.

In most cars, if the engine is turning the electrical system (in the ignition on state) WILL generate these pulses. This is not the case in most hybrids. I'm pretty sure there are also non-hybrid models that can do this, but I can't name them.

 

[Eisenson]

In most cars, if the engine is turning the electrical system (in the ignition on state) WILL generate these pulses. This is not the case in most hybrids. I'm pretty sure there are also non-hybrid models that can do this, but I can't name them.

You have it right - my "ignition" is the low-voltage pulse that travels to the transformer mounted near the spark plug, which converts to a high-voltage pulse that jumps the gap. In other cars, that transformer is the "coil", and there is one of them. In this car, there's one per plug. Most tachs count those low-voltage pulses and do some arithmetic to generate the RPM display.

The Prius ECU shuts down the power-generating aspects of the engine (fuel + spark plugs) often, even at highway speeds, and the ICE becomes only an air pump.

It's 6:36AM, and I just returned from another experimental drive with the ScanGauge. It didn't change overnight and is still the geekiest addition possible for our cars. In fact, you don't really need to be such a driven geek to enjoy and use many of the functions, which are highly tutorial.

Henry

 

[richard schumacher]

When would the engine be spinning with the ignition off?

(1) When it is being spun up without fuel or spark in preparation for running, and (2) during engine braking.

 

[hyperion]

How could these conditions occur with the ignition (power button) off?
I'm speaking of normal car operation.
I believe you are speaking of no spark to the plugs,
This would be still acceptable indication that the ICE was not running.
The tach when indicating rpm would be as good as an "engine run light."

 

[Eisenson]

I have Coastal's gadget that shows ENGINE-RUN and BRAKING/REGEN. An LED is connected to the power supply of the electric fuel pump. Start the car, and seven seconds later the LED illuminates as the engine starts. I was surprised to see when that light turns OFF, however.

...when cruising at 35mph on flat streets
...when decelerating at 70mph on the highway
In fact:
...whenever the engine is warm and the foot comes off the accelerator pedal

Interesting, isn't it?

Now, with the tach function in the ScanGauge I'll be able to see when RPM appears to drop. I think it's in perfect synchrony with the fuel pump power, so when the engine isn't producing power both fuel and ignition are OFF.

 

[GlacierBobby]

Sounds a useful piece of instrumentation. Anyone know if it's compatible with the European 2004?

 

[DanMan32]

However, additional information one would need: MG1/2 voltage,current,RPM, HV battery current (in and out) and voltage, etc. None of that is going to be found in a generic scanner.

 

[hyperion]

Everything you could desire in a set of instruments can be found in this one and you certainly can't beat the price.

 

[Brian]

Everything you could desire in a set of instruments can be found in this one and you certainly can't beat the price.

I agree with Dan though, I would really like to monitor those things more!

 

[Eisenson]

That MiniScanner group on Yahoo is planning to extract and display everything. Unfortunately, the availability of this ScanGauge will probably pull many participants from that project - and it may die.

I'm thinking of remotely reading the HV supply, but in truth this little box does nearly everything I could ask for. I'm about to pull it apart and install the guts into my dash. That might satisfy my geek gene for a while.

 

[hyperion]

I wouldn't even think of fooling with the big batteries or any part of this system. This is the new technology it took Toyota years developing so that a hybrid would be feasable and not even a Toyota dealer knows anything about it.
Now the small motorcycle sized 12 volt battery which is buried in the trunk and used to fire up everything in the car is a different animal and something everyone would like to know it's constant condition. The scanner would be worth the price, just for this.

 

[Eisenson]

The ScanGauge shows the instantaneous voltage of the little 12V (really 13.6 most of the time) battery. I was thinking of a high-impedance (no current flow) line to some convenient point in the high voltage system, so I could read that separately.

However, it's also possible that the information is somewhere in the OBD2/CAN data, in which case it's just a software matter - and I bet the ScanGauge people can find it.

 

[c4]

Do the MPG and trip computer features work with the Scangauge? If so, do the MPG readings (both instantaneous and tank) show any agreement with the MFD numbers? Are decimal places displayed with any of the numbers? (I realize that 0.1 MPG is really insignificant, but the value in seeing a decimal place is not accuracy, but an indication of consumption trend- ie, a +/- 0.1 change tells you whether consumption is going up or down which is a big plus for those of us in Canada and certain other countries with our crippled MFDs reading in L/100km- and speaking of metric- are the display units on the Scangauge switchable to metric, or are they imperial-only?)

The Scangauge does sound like a useful instrument- if the MPG calculation functions work and show decent agreement with the MFD, it would be about 90% of the way there.. The only other features I'd love then would be an absolute traction battery SoC reading and charge/discharge rate a-la Miniscanner (ie, showing the battery SoC in an absolute percentage and also the charge/discharge current into the traction battery (both figures are very useful for maximizing braking regeneration and for those with good pedal control or an EV button, when to allow the car to switch into stealth)..

 

[BIF]

When would the engine be spinning with the ignition off?

(1) When it is being spun up without fuel or spark in preparation for running, and (2) during engine braking.

And...

(2) when driving faster than 42 MPH and the computer decides that the ICE isn't needed; ie - going down a hill on the freeway. The computer shuts off the spark and compression, but lets the engine's internal parts keep spinning, so that MG1 won't have to spin it up to restart it.

 

[hyperion]

Then the span guage with rpm selected which goes to zero when fuel and spark are denied will in effect give you that elusive engine run light information. As stated, the driver was amazed at all the situations when the ICE shuts down. Backing off on the accelerator at 70 mph on a level freeway ect; and then seeing the engine start when the accelerator is just "touched" at 68MPH.
Mine will be mounted on the dash in front of the driver showing RPM--coolant temp--voltage--and oil pressure if that is available. (permantly, as I have no further use of the guage. The MFD gives me enough other info.)
This is one really inexpensive way to secure some engine information finally.

 

[DanMan32]

I wouldn't want to buy a $100 scanner just to read the 12V supply voltage!

The diagnostic screen on the MFD reads the voltage quite nicely. A cheap DMV from RadioShack (or home depot for that matter) would also do well.
And considering the inverter's DC/DC converter keeps the 12V supply quite constant would further negate getting a scanner for aux voltage.

Now getting a more accurate reading of the HV SOC would be a different matter.