JOBD on Japanese models?

Yousuf Khan · 2010-07-05T17:36:19+00:00

Hi, sorry for the slightly off-topic here, I asked on the Toyota newsgroup, but it seems to be a newsgroup in turmoil (off-topic outnumbers on-topic). I'm currently in a country which gets a lot of used right-hand-drive Toyotas straight from Japan. I have my OBD-II connector plug for my laptop with me, and I was about to try to read the codes from a '98 Corolla, when I found out that these models don't have a JOBD port. Later I found that some 2004 models of cars had these connector ports. So does anyone know when these ports became standard on Japanese-model cars? In North America, they became standard after the 1996 model year. Yousuf Khan

Jul 05, 2010 26 Replies

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Yousuf Khan 16 years ago

Just an update. I found out later that even 2001 model JDM vehicles had the JOBD plugs, so it looks like JOBD and EOBD came online at around the same time, 2001.

Yousuf Khan

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jayden 10 years ago

replying to Catherine Jefferson, jayden wrote: JOBD is definitedly design for Japanese vehicle. As there is OBDII for america, EOBD for eroupe. Japanese vehicle has their own special protocol. So they develope their own communication protocol for their car.

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jayden 10 years ago

replying to S, jayden wrote: Steve is a pro, the explaination is perfect.

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clare 10 years ago

Would make life a whole lot simpler if all markets used the same propocol - if what you say is true Subaru has to make a minimum of 3 different versions of every computer - and possibly different harnesses as well?

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Yousuf Khan 10 years ago

I'm pretty sure OBDII, EOBD, and JOBD are all compatible protocols more or less. Maybe a few unusual codes are different between them, but the basics are the same.

Yousuf Khan

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clare 10 years ago

All 3 standards are implemented in almost identical methodology, using the same SAE J1962 pinout and connector. Only the actual "regulation" has any appreciable difference. Within the OBD2 standard there are 5 different "protocols" used. Each protocol uyses a different pulse train - with different frequencies and coding. SAE J1850 PWM (pulse-width modulation - 41.6 kbit/s,) is the standard of the Ford Motor Company.

SAE J1850 VPW (variable pulse width ? 10.4 kbit/s) is the standard of General Motors

ISO 9141-2 .(This protocol has an asynchronous serial data rate of

10.4 kbit/s. It is somewhat similar to RS-232; however, the signal levels are different, and communications happens on a single, bidirectional line without additional handshake signals.) ISO 9141-2 is primarily used in Chrysler, European, and Asian vehicles

ISO 14230 KWP2000 (Keyword Protocol 2000) I'm not sure how this one works or who, if anybody, currently implements it.

ISO 15765 CAN (250 kbit/s or 500 kbit/s). The CAN protocol was developed by Bosch for automotive and industrial controllers. Unlike other OBD protocols, variants are widely used outside of the automotive industry. While it did not meet the OBD-II requirements for U.S. vehicles prior to 2003, as of 2008 all vehicles sold in the US are required to implement CAN as one of their signaling protocols. It is used in conjunction with one or the other of the standard prorocols on most current vehicles.

Your scanner can tell which protocol to use by a combination of which pins are used and the frequency and/or voltage on the pins..

On top of the mandated OBD2 standard, many manufacturers supply a lot of other data from other systems on the car through the OBD port using a "standard" or "protocol" called EOBD2 - which is not "European" but "enhanced".

Some EOBD2 codes can be read by some basic OBD2 scanners, with better/later scanners also able to read CAN bus codes , and the higher end units capable of reading the EOBD2 codes of MOST manufacturers. No manufacturer is "required" to make their codes available on generic code readers and some may choose to require specific diagnostic equipment to access these codes.

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