For those that don't know, the CONSULT is a handheld computer that the dealer hooks up to your Nissan to read error codes, voltages, temperatures, set up the engine for idle adjustment, timing etc. For Nissan and many other car manuf, this data bus/stream is proprietary and isn't shared with the public.

That said, I see that there are a few companies out there selling aftermarket 'widget's' that tap into this diagnostic port and report things like MAF voltage, RPM, coolant temp, etc. (ie: the Techtom stuff). Pretty neat, specific widgets.


Well, I'm a tinkerer/programmer/EE/test engineer that has always wanted to know more about the Nissan ECU's data stream, how to pass and read parameters, etc.

Anyone out there have any information they can share about this data bus? Speed, bits, framing, etc? I'm looking to use this for data logging.


TIA

Dont know that much about the ECU's but that whole
semiconductor wafer prober machines thing is too damn much.

Dave--

Our resident electrical engineer-type, aka Ben Moses (bmose), spent some time this year diving into this very same subject. He ended up not being able to decipher the proprietary code that Nissan used on B13s.

This is why JWT can still get away with $5-600 for an ecu reprogram.

I hope you find what you're looking for, but don't bet on it. The Techtom stuff is the easiest solution, IMHO. That's why I did the GB on it, while we can still get the OBD-1 stuff before they stop making it.

Good luck.

the data is digital and is sent in packets. if you get a wire diagram from an fsm you can determine which wires send which signals to the techtom units. you can observe through testing the stream. proprietary code, thought you said you were EE's??? those obdI units are over 10 years old. shouldnt be too difficult. not a whole lot of tuners can sucessfully performance tune a car for daily driven status. JWT has managed to do this fairly well for many years. that kind of reliability and experience is worth the money they charge. if you want race tuning go buy a standalone and do it yourself if you think you can do better.

Gee, thanks for reposting what I said here
Speed, bits, framing, etc? I'm looking to use this for data logging.

I also state the stream is proprietary. Also note I said I plan on using it for data logging and also note that I did not ask for a pinout.

Thanks for adding no additional information to this thread.

Dave
Tuning? Where do I say tuning?


Originally posted by bigtom
the data is digital and is sent in packets. if you get a wire diagram from an fsm you can determine which wires send which signals to the techtom units. you can observe through testing the stream. proprietary code, thought you said you were EE's??? those obdI units are over 10 years old. shouldnt be too difficult. not a whole lot of tuners can sucessfully performance tune a car for daily driven status. JWT has managed to do this fairly well for many years. that kind of reliability and experience is worth the money they charge. if you want race tuning go buy a standalone and do it yourself if you think you can do better.

Well I don't know about the encapsulation or framing mechanisim used for the data stream.

I was under the impression that you would not require to 'decrypt' any of the proprietary nissan codes, since you're monitoring voltage signals ? I know you're looking to monitor this signal and not modify it. I know I'm stating the obvious but that is all that an AFC or E-manage is doing, is taking this signal and modifying the voltage sent to the ecu.

If you're so inclined to you can come up with something like Alex Peper http://www.obd-2.com/ for obd I by monitoring the incoming data through the consult jack and send the signal over a COM port to software to interpret. There is a handful of reference on his website for monitoring ODBII perhaps it will help you with OBDI ?

As far as anyone having any information to 'decrypt' the Nissan ROM and injector drivers etc.., these guys http://eficlub.hypermart.net/main.html I believe have, unfortunately I don't speak Taiwanese.

Originally posted by art_from_ct
I was under the impression that you would not require to 'decrypt' any of the proprietary nissan codes, since you're monitoring voltage signals ? I know you're looking to monitor this signal and not modify it. I know I'm stating the obvious but that is all that an AFC or E-manage is doing, is taking this signal and modifying the voltage sent to the ecu.
No, he wants to read the CONSULT port. Without detailed documentation, it would be pretty damn hard. Considering the price of a MDM-100, not worth IMHO.

Isn't the consult port the same one as the OBD port ? If so then aren't these the same signals coming from the ECU to this port ? I was under the impression that the dealer uses the same port to hook the consult up to ?

I don't see how logically this port could be recieving different information OTHER than the ECU ?

If an mdm-100 is able to recieve some proprietery nissan information other than what is available in the ECU, I'm curious as to what it could be.
Looking over the the list of available variables to monitor I don't see anything that the mdm-100 does through the consult port that you can't do with ANY decent OBD II scanner, including one made a skilled individual such as the one made by Alex Peper. Software based or neat LCD display, whatever floats your boat.

It doesn't require TONS of proprietery documentation relating specifically to nissans.

Please correct me if I am wrong, as I would like to be informed about this topic as well.

Art,

Yes, this is the same port that the CONSULT is plugged into. This is the ONLY data port coming from the ECU. There are no signals other than a data stream coming from this port.

This data stream is digital, has a format, and is a format that is not 'standard' hence it is proprietary. What order the bits are sent, the number of bits, the format of the word, the framing of the data, what the data is, speed, etc is not publicly known.

Lastly, my 1991 is not OBDII. The government did not require manufacturers prior to OBDII implementation to have an 'open' data bus, and even now it is not fully documented.

If you find a web site or publication that decodes this data for a 1991 non OBDII SE-R stream, or ANY non OBDII Nissan data stream (heck even OBDII) please send it my way. I have yet to find this info.


Looking over the the list of available variables to monitor I don't see anything that the mdm-100 does through the consult port that you can't do with ANY decent OBD II scanner, including one made a skilled individual such as the one made by Alex Peper. Software based or neat LCD display, whatever floats your boat.

Huh?!

Dave

If you want data logging... check out www.pocketlogger.com It requires that you have a palm but it plugs straight into the consult port I believe. And it's cheap too. Since I don't have a Palm, i'm just going to go with the CMX :)

Khiem

oh if you got say a thousand bucks lying around, you can always buy one and play with it

http://cgi.ebay.com/ebaymotors/ws/ebayISAPI.dll?ViewItem&item=1848364686&r=0&t=0

Buying this is not going to help me one bit. I have a true interest in understanding what is going on here. Buying a CONSULT is not going to tell me what the data stream is, nor is it going to help me design my own data logger for my own use.

I wouldn't think I'd be breaking ground on this since Nissan's with on board diagnostic ports have been around for a while, but I guess I am (at least in this crowd).

Time to break out the deep memory logic analyzer. . . . . .

Originally posted by UcLaGeE
oh if you got say a thousand bucks lying around, you can always buy one and play with it

http://cgi.ebay.com/ebaymotors/ws/ebayISAPI.dll?ViewItem&item=1848364686&r=0&t=0

Thanks but it only works with OBDII ECU's.



Originally posted by spdracerUT
If you want data logging... check out www.pocketlogger.com It requires that you have a palm but it plugs straight into the consult port I believe. And it's cheap too. Since I don't have a Palm, i'm just going to go with the CMX :)

Khiem

Originally posted by Probedude

If you find a web site or publication that decodes this data for a 1991 non OBDII SE-R stream, or ANY non OBDII Nissan data stream (heck even OBDII) please send it my way. I have yet to find this info.

Dave

Reread my post for a website I posted. As I mentioned before I do not speak Taiwanese hence being of no help to me.

Well to get you started, Nissans use an ISO interface, it uses a data format that a standard PC UART can read. So find an ISO connector mated to a RS232 port and go at with your serial data protocol analyzer.

You could always call up JWT or JUN or G-FORCE and ask how they do it, as I'm sure there willing to share.. ;)

Art,

Dave has a valid argument and you seem to be missing his point.

He wants info on the format/protocol of the data coming out of the Consult/OBD-I port of a pre-1996 Nissan. (Don't we all?? :) )

Clue as to how valid his argument is: There are dozens of OBD-II scanners on the market. There is NOT ONE Nissan pre-1996 scanner south of US$1000! Don't you think that someone/somewhere would have come up with such a gizmo if it was easy? GRID in Japan sells such a setup (cable + software) for USD 900.

Originally posted by art_from_ct

Reread my post for a website I posted. As I mentioned before I do not speak Taiwanese hence being of no help to me.

The site you mentioned has NOTHING to do with Consult or reading the data port in any form. They only play with their ECUs (reprogramm them). They use a free ECU-ROM-Editor and by trial and error the get some extra HP from their engines, imitating what JWT or the others do.
And they are not Taiwanese. If they were there are a lot of Taiwanese people ready to "offer" their translating help. Unfortunately the site is in Thailand, and Tai is a much more obscure language than Taiwanese.


Well to get you started, Nissans use an ISO interface, it uses a data format that a standard PC UART can read. So find an ISO connector mated to a RS232 port and go at with your serial data protocol analyzer.

Again, stop thinking OBD-II. In pre-1996 cars Nissan uses an ISO connector. This much is true. However, there is NO info on what data is passed over the conector, their format, the commands used to "interrogate" the ECU for the data, NOTHING. It certainly is NOT a "data format that a standard PC UART can read".

You could always call up JWT or JUN or G-FORCE and ask how they do it, as I'm sure there willing to share.. ;)
Well, I am sure I know how JWT and JUN do it. With a Consult or with a US$1000+ contraption from Japan...:)

Chris

Originally posted by art_from_ct
If an mdm-100 is able to recieve some proprietery nissan information other than what is available in the ECU, I'm curious as to what it could be.
Looking over the the list of available variables to monitor I don't see anything that the mdm-100 does through the consult port that you can't do with ANY decent OBD II scanner, including one made a skilled individual such as the one made by Alex Peper. Software based or neat LCD display, whatever floats your boat.


I am using an OBDII scanner right now and it sucks. The Alex Peper one. I'm borrowing it from someone. It drops off all the time(looses its connection), it's really finiky to get working right with your car, and is really only great for viewing and clearing codes.

All the OBDII scanners I have seen show MAF in some dumb value, # of flow per minute or something. The Apexi Multichecker, any of the Techtom products, and Consult show this in very usable VOLTAGE. Same issue with very important O2 and TPS.

When you're diagnosing your car you need these in Voltage. That's what the FSM has them listed under for checks and also what JWT will be asking you for if you need help from them.

I think the reason why OBDII scanners read it this way is because the standard for OBDII data is in this format. This format does nothing for us. Devices who can read Nissan's proprietary code get the info we need in the values we can use.

Believe me, I wouldn't have known the difference myself just a month ago before I started trying to hunt down possible problems with my setup.

Originally posted by hpro123
Clue as to how valid his argument is: There are dozens of OBD-II scanners on the market. There is NOT ONE Nissan pre-1996 scanner south of US$1000! Don't you think that someone/somewhere would have come up with such a gizmo if it was easy? GRID in Japan sells such a setup (cable + software) for USD 900.

It seems like you have answered your own question.

And they are not Taiwanese. If they were there are a lot of Taiwanese people ready to "offer" their translating help. Unfortunately the site is in Thailand, and Tai is a much more obscure language than Taiwanese.

I wasn't sure which language it was, my browser defaulted to Taiwanese, I assumed it was correct, thank you for clarifying that.

Again, stop thinking OBD-II. In pre-1996 cars Nissan uses an ISO connector. This much is true. However, there is NO info on what data is passed over the conector, their format, the commands used to "interrogate" the ECU for the data, NOTHING. It certainly is NOT a "data format that a standard PC UART can read".


I see your point, I disagree that there is NO info on the data being passed in pre-1996 Nissan cars. No I don't know where to find it ,if I did I would certainly share.

I was under the impression that when something gets an upgrade like a nissans ecu, usually the newer version is more difficult to 'uncover' and figure out and not the other way around, kind of like most computers.

Originally posted by art_from_ct

I see your point, I disagree that there is NO info on the data being passed in pre-1996 Nissan cars. No I don't know where to find it ,if I did I would certainly share.

OK Art, let me re-phrase since your statement is correct.

Obviously, somewhere out there, ALL the info regarding pre-96 Nissan car diagnostic port connectors is available. GRID.CO.JP has it since they sell complete packages that can monitor in real time everything happening in the ECU, Techtom has it, Consult has it.

Unfortunately, none of this info is available to us. I have not been able to locate it and, believe me, I have searched everywhere (not only on the free and non-free Internet) but I was unable to find even rudimentary info.

I was under the impression that when something gets an upgrade like a nissans ecu, usually the newer version is more difficult to 'uncover' and figure out and not the other way around, kind of like most computers.
You are correct in this respect too.

Newer Nissan ECUs have been proven "hack-resistant" until now. JWT that has a stellar track in tampering with Nissan ECUs has been unable to break into post 96 ECUs (or post 98, I don't remember which).

However, since 96 OBD-II has practically nothing to do with the ECU. OBD-II is a well defined and well documented industry standard that is applied to all ECUs, which are quite different.

Your analog with computers can be used here. Think of OBD-II in the same light as TCP/IP. I can read data from TCP/IP without having any knowledge of the underlying hardware. Same with OBD-II. Commands to retrieve data and the (protocol &) format of the returned data is the same for all cars.

As a side note & closing comment to this, maybe we will soon get lucky! The US legislation is about to be changed and "force" all car companies to disclose all and any diagnostic, maintenance and tuning data to all interested parties (shops, individuals, etc.) in order to "facilitate" fair trade. If this passes we may soon have the info available.

Chris

Pretty disappointing results today. I took my digital scope/logic analyzer out to the car hoping to capture some data streams and found that there is NO data streaming from the ECU when I probed the CONSULT connector.

I found power signals and the Rx line was sitting at 1/2 of the battery voltage, but the TX line and CLK lines were at gnd potential, even with the engine running.

So, I'm still completely lost as to how to get info in and out of the ECU.

Can anyone verify that even the lowest Techtom unit (CMX100) uses more than 3 wires to hookup to the CONSULT port?


Can anyone post or PM me any information on what the data stream looks like, number of bits, bit order, commands, returns etc etc. Does the ECU stream data out once it is given a command or does it only return 1 value for each query?


ANY help on ANY info in the previous sentence is much appreciated.

Dave

im sure that is correct. why would the ecu shove data to the port all the time? that rx port is there open waiting for a signal, now what that is who knows. Id say if its probaly like 12v or something like that. ecu gets the signal then it starts pushing data. and at the same time i doubt it would send EVERYTHING, probaly what you have to do is send a signal of what you want. As when you are messing with the consult you put in what you want to read at what point. then it starts showing the data.