Automotive gurus

[Diesel1]

My goal is to build a few controllers to command certain functions on the new diesel trucks. Starting with a torque converter controller that overrides the factory functions giving the user full control of commands.

I can control it with my scan tool via the obd 2 port. So is there some sort of recorder that I can listen to the can bus system and make the command I want then just duplicate it using a programmed circuit?

Basically I'm just looking to lock and unlock the torque converter using a hard wired handheld remote. Oh and trying to not set any ECM codes while this command is in place!?!?

 

[Solidus]

The answer to that, in short is both yes and no.

Yes, in the sense that you can "sniff" the line or look up the different codes and implement them in programmable hardware.

No, in that implementing that will require significant hardware design.

The OBD-II port is a combination of hardware (the physical connection) and hardware-level transceivers that uses a differential line, much like Ethernet and USB. The actual signal protocol appears to vary by manufacturer. You can read more about the protocols involved here.

That being said, it is a doable thing if you have experience with hardware design. I may be able to advise or help on that front should you choose.

Here is a FAQ, and if you see "Does my car have OBD-II", you can get an idea of how to determine what specific standard is being used.

Actually, it might be more simple than I initially thought.

If you use a USB-OBDII adapter (like this), you can bridge a serial link using an FTDI chipset to an Arduino or something of that nature. In that case, you'd just have it read a switch or button and send a corresponding hex or other command down that serial line.

Let me know - I've worked with specific protocols before, so if you can give me a better idea of what to do or how to do it, I can look up the specific commands for you. Problem with direct sniffing the line is there is a bunch of communication that goes on between vehicle and scanner - identification, signaling, acknowledgement, packet encoding, that makes it not as simple as just wiring to the connector and looking for magic.

 

[jcurrie]

i assume that you are talking about standard pickup trucks having had a brief run in automotive opening and closing the TCC can be done but as for not setting codes you would have to reflash the ECM or PCM

 

[Externet]

The torque converter clutch TCC is engaged by a solenoid; there is no pulse modulation mode I know of. It is either energized or not.

A plain switch should be capable of controlling such.
I made two circuits and installed them in my 2 classic cars, they engage TCC at about 45 mph, with a potentiometer to select the activation speed whose signal is taken from the transmission tail sensor. It had the manual switch implemented also but ended removing it and now obeys a 2917? IC only.

If error codes could be generated by tampering with stock circuits, a resistor could take place to fake the presence of the solenoid load.

The switch can put a resistor into the wire to force disengage and another switch position to force engage.

In other words, A switch will provide 'auto' or 'manual' control and the compfuser on board will sense nothing wrong.

 

[jcurrie]

that would work with older TCC but the newer ones have a duty cycle control unit which works with the TCU .

jc

 

[Externet]

Thanks for clarifying about the new types.

Well, then the switch method would not fake a PWM; just do the manual on/off.

 

[jcurrie]

yea the newer they are more and more interconnected they are the PCM/ECM talks to the TCU which in turn connects to the DCC which controls the TCC through the TCU. all for the better or worse depending how you look at it .
jc

 

[russian]

Sniffing and sending CAN messages is pretty easy - here is my experience

 

[jcurrie]

a word of caution Diesel1 don't try anything till the warrenty runs out , worked for a dealership once any kind of mods and out went the warrenty.
jc

 

[Diesel1]

Any one able to help with the construction of this piece of hardware would be compensated for their experience and time. [email protected]