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Questions and Answers

If you have a question about the Prius Mini-Scanner that is not answered on this page, please contact ECROS Technology.

Why was the Prius Mini-Scanner Discontinued?

It is only economical for me to manufacture the Prius Mini-Scanner in batches of 50 or more units.  At the time the last batch ran out, the number of orders coming in had trailed off to about half-a-dozen per year, so a new batch would have taken about ten years to sell.  With the changes to the 2004 model year and the Prius becoming a main-stream car it seemed to me that the need for the Mini-Scanner was just about over.  Therefore, I decided not to make another batch.  This does, I'll admit, ignore the need for a diagnostic device for the 2001 to 2003 model year Prius as they get older and owners need maintenance help.  But, the number of queries I get about the Mini-Scanner is only about one per year, so overall I don't think that there are enough buyers to justify re-starting production.  One final deterrent to producing more Mini-Scanners is that while they are in warranty I am obliged to keep my 2001 Prius to support any returns.  The car is over ten years old and I would like to be free to replace it.

May 2011 - However, here is someone who disagrees and is collecting deposits for a new production run.

Is the Mini-Scanner Safe to Use in My Car?

I have designed the Mini-Scanner according to the relevant industry standards, particularly ISO9141-2.  By design, it meets the requirements of a diagnostic tester, with the exception that it cannot sink 2 amps from the K and L lines, but I'm damned if I can see how this need can arise.  (Note that most other DLC adapter circuits published are less in compliance with the standard even though they claim full compliance.)  In addition, the vehicle power is protected by a ferrite core against electrical interference and a 250 mA self-repairing fuse against overcurrent.  I have had a Mini-Scanner permanently connected to my own car for more than six months and more than 30 others are in the field.  So, from an engineering point of view, I have done all I reasonably can to make sure the Mini-Scanner will not hurt your car.

However, you must use the Mini-Scanner in a safe and responsible way.  Operating it (other than glancing at the display) while driving will reduce your attention to road conditions and traffic and may be unsafe.  I strongly recommend that you don't do this and I take no responsibility for anything that happens if you do.  In fact, I require you to sign an agreement to this effect when you purchase a Mini-Scanner.

Will the Mini-Scanner Work with Cars Other Than the Prius?

The short answer to this question is No.  This is because I intend to concentrate on the development of software for the scanner to work with the Prius.  The hardware of the mini-scanner is suitable for operation with other cars, especially those using the ISO 9141-2 protocol on the diagnostic bus.  However, the Prius also supports the ISO 14230 "Keyword Protocol 2000" (KWP2000) and this is what I will be using.  There are two important reasons for this choice.  First, the Prius has multiple ECUs (computers) and many pieces of information are present in more than one ECU.  Using ISO 9141-2, the scanner broadcasts a request for information and all the ECUs that have that information respond one after the other.  In most cases, we only want the response from one ECU.  For example, when we ask for the engine r.p.m., we only want the response from the Engine ECU.  The response from the Hybrid Vehicle ECU is not the measured r.p.m. but is probably the value it has requested from the engine.  Using KWP2000, the scanner can ask a specific ECU for information.  This avoids having ECUs do work unnecessarily, clears the bus more quickly for the next message and simplifies receiving responses.   Second, the length of an ISO 9141-2 message is not explicitly encoded in the message.  Quite apart from the additional difficulty of sending and receiving such messages, this is in my opinion a serious design flaw and I am much more comfortable with the better design of KWP2000.

Will the Mini-Scanner Work with the 2004 Model Year Prius?

Unfortunately, no.  Toyota have changed the way that their scanner gets at diagnostic information in the 2004 car.  Information mandated by law is (presumably) still available on the ISO 9141-2 bus, but all of the interesting stuff has been removed and is now accessed using a CAN (Controller Area Network) bus.  There are no definite plans at this time for a Mini-Scanner for the 2004 Prius.  Connecting to the CAN bus is not a problem as it still appears at the Diagnostic Link Connector.  The difficulty will be discovering the format of the messages that are sent on the bus to get information from the car.

How do I Fix the Mini-Scanner in Place behind the Steering Wheel?

Not everyone will want to fix the Mini-Scanner in their car in the same way.  If you don't mind sticking something to your car, the simplest way to mount the Mini-Scanner is with adhesive Velcro™ tape.  You can then put it wherever you like.  The Mini-Scanner comes with a small aluminum bracket that can be clamped to the dash by the adjustable steering wheel assembly.  If you stick the Velcro™ to this bracket, you can later remove the Mini-Scanner and the car will be unmarked.

Please make sure the Mini-Scanner doesn't come loose while you're driving as this will be very distracting to the driver.  I have found it best to have the display pointed at my chin to avoid reflections and get the best contrast.

I Left my Car in the Hot Sun and the Mini-Scanner Display Went Black.  Is it Broken?

No.  This is what happens to Liquid Crystal Displays (LCDs) when they get hot.  Everything will be OK again when it cools down.  Mind you, like all electronic equipment, the Mini-Scanner will not like high temperatures.  If you're going to leave the car in hot sun, you might want to cover it to keep the sun off it and maybe not turn it on until the car cools down a little  Also, if you take it apart to spray paint the case, note that darker colors will cause it to heat up more.