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Discussion Starter #1
The DTC pictured in the repair manual looks like a pretty simple device. Has anyone looked into what it would take to make the port talk to a laptop or something?

Having spent my $10 and downloaded the entire repair and wiring manuals, I now realize they do little good without the DTC...
 

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The DTCs could probably be read by any CAN compatable code reader. Getting other diagnostic information and performing active tests and proceedures is another matter.

Autozone will read your DTCs for free.
You have the repair manual, so once you have the DTCs, you can decipher the DTC and possibly help diagnose the problem.
 

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Forgive my ignorance or bad English, or maybe I am only tired a bit, but I was having trouble understanding what a DTC device is. Maybe I just don't have the referred pages from the manual... Can you explain what a DTC device is ?

If the DTC in your message stands for Diagnostic Trouble Codes, than they are definitely available on the CAN and can be even cleared... The only "trick" is, that the upper 2 bits define if they are P/U/etc.

Attila
 

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Naw, your English is fine. jimg misused the term DTC, and I didn't spot it.
DTC: Diagnostic Trouble Code. It is the ID of the problem the car detected. The device you see in the repair manual to READ DTCs is a THHT: Toyota Hand Held Tool. Basically it is a specialized PDA with special software that can do a whole lot more than just read and clear DTCs. It can be used to update the car's software, manually operate different things in the car to perform tests and procedures, and can be used to change customized settings for your preferences. It can also read the car's status, such as battery voltage, current, MG voltage/current/power, engine vitals, etc.
Pretty shnazy tool. I wish I could afford to own one.
 

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Trouble codes

Oh, I didn't realize that. The Prius is not a standard OBDII car?
 

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All cars and light trucks built and sold in the United States after January 1, 1996 were required to be OBD II equipped. In general, this means all 1996 model year cars and light trucks are compliant, even if built in late 1995.

Two factors will show if your vehicle is definitely OBD II equipped:
1) There will be an OBD II connector, and
2) There will be a note on a sticker or nameplate under the hood: "OBD II compliant".

Here is a website:

http://www.obdii.com/connector.html
 

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ODBII however allowed for manufacturer dependent codes. However, most of the codes the Prius puts out even for hybrid component problems are prefixed as standard ODB codes, rather than manufacturer specific.

But again, DTC is a code (it its the C in DTC) and not a device. Devices generate or read DTCs. There is a standard for DTCs as of 1996, although even that standard has deviations on how to present the DTCs. There are something like 4-6 accepted methods of transmission of data across that DLCIII, the latest being CAN.

But ODB only specifies errors and such that need to be available to a reader and technician mostly for emissions. It does not disallow additional proprietary functions that might be used to perform tests, produce operations for repair or diagnostics (such as opening/closing valves, running pumps, actively displaying switch/sensor outputs), or change settings, especially settings not related to the drive train, such as alarm settings, door lock settings, etc.
There is or was talk in congress to do more standardizations, and to have manufacturers disclose communications, so that third party tool developers could emulate those functions, as it is unfair to independent repair centers that they have to buy specialized scanners for each manufacturer or be locked out of being able to do repairs on vehicles.

At the very least, software should be obtainable at a reasonable price that can be installed on standardized PDAs and/or computers.
 
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