Engine code reader pre OBD II

magg · Post by **magg** » Sun Jan 09, 2011 2:34 pm

More ramblings from the novice. Just so we are on the same page. The package you have has s/w that gives you SSM & OBD2 capability? You can get it to work on the Outback in both modes? But will not talk to the Forester in either mode?

Gannon · Post by **Gannon** » Sun Jan 09, 2011 3:36 pm

The package i got only does OBD2, and only works on the 2004 Forester (because it is OBD2 compliant- has 2 oxygen sensors)

I bought a TTL to RS323 USB adaptor to communicate with Subaru Select Monitor

magg · Post by **magg** » Sun Jan 09, 2011 5:10 pm

Have I got the config correct: vwrx.com SSM s/w & TTL/USB adapter s/w loaded, TTL input pins on TTL/USB adapter connected to SSM pins in OBD2 connector & USB output to pc.

Gannon · Post by **Gannon** » Sun Jan 09, 2011 5:42 pm

From doing a little reading, the reason im having trouble is because the signals need buffering (or something like that)

There was a circuit i found that used an op amp and a few other components to clean up the SSM signal. Im going to do this soon.

The first thing i want you to do is find out if your car is OBD2

Count the oxygen sensors, if there are 2, one on the front of the cat where the 2 header pipes join, and the 2nd is either on the back end of the catalytic converter, or a few inches downstream the pipe.

The other way to tell, is the IAT sensor. If there is a little sensor on the front of the air filter box, there is a good chance that your car is also OBD2 compliant.

magg · Post by **magg** » Sun Jan 09, 2011 7:38 pm

Your TTL/USB adapter is a buffer/level translator. The TX SSM signal should feed into the adapter Rx pin & the Rx SSM signal does to the adapter TX pin. GND goes to GND. The +5 is not needed.

The USB driver s/w should be loaded and configured for a virtual serial port for your SSM s/w.

Not my intention to offend if my assistance is only repeating things you have already tried.

Will have a chance to check my car's OBD2 status tomorrow.

magg · Post by **magg** » Mon Jan 10, 2011 3:56 pm

Suparoo, been doing some more investigation & if you have the same OBD II to DB9 cable that I do, then SSM will not work because the appropriate connections are not passed through. Makes sense as the cable was sold as ODB II not Subaru SSM. Will recheck to confirm & if I cannot get OBD II to work will modify my cable to get at the SSM signals.

Have checked my OBD II connector & have same pinouts as you. Do not appear to have the IAT sensor although I have an Impreza RS. Will need more time to check for two O2 sensors.

Gannon · Post by **Gannon** » Mon Jan 10, 2011 4:34 pm

Yup i have the Tx hooked to RX and the Rx hooked to TX, Gnd to Gnd, no Vcc needed.

I tried with a HEX communicator tool last night and had no luck, could not get the ECU to respond to any of my read memory commands

I really need an Oscilloscope to see if i can see data pulses and work out why i cant get anything

magg · Post by **magg** » Mon Jan 10, 2011 4:58 pm

Have scope & know Bowraville well but a bit far from the Blue Mountains. Have you confirmed that the SSM signal wires actually appear at the 9 pin connect. I suspect they do not as I have belled my cable with the following results:

OBD/D9
16/9
15/8
14/5
10/6
7/4
6/3
5/1
4/2
2/7

No 12 or 13 which I beleive are the SSM signal pins.

Gannon · Post by **Gannon** » Mon Jan 10, 2011 7:31 pm

Yeah the SSM pins definitely have nothing to do with any OBD2 product.

I used the OBD plug to house the FDTI adaptor, and just connected the Rx Tx and Gnd wires to pins 12, 13 and 5

d_generate · Post by **d_generate** » Tue Jan 11, 2011 4:46 am

Not sure if this will help but "ALL" WRX & STI's in Australia are OBD11 from MY99 onward. If you've got 2 little single wire black plugs hanging near your steering column just plug them together, turn on ignition & count the flashes on your check engine light 3 long & 2 short is code 32 ........... disconnect Batt for 20min to clear.

magg · Post by **magg** » Tue Jan 11, 2011 3:09 pm

Suparoo you have been busy, hense my comment "not my intention to offend". Only thought is have you tried crossing Tx & Rx connections.

magg · Post by **magg** » Wed Jan 12, 2011 8:28 pm

Been doing so more research into OBD II for oz cars & most sources claim that imports from 2002 could be compatible, oz build from 2004 could be & all oz cars after 2006 must be. USA cars from 1996 had to be OBD II but Subaru might have built special non OBD II cars for oz.

Suggests that my Impreza may not be OBD II & your Outback unlikely to be OBD II compatible.

Also, regarding your USB/TTL adapter no go, might be a silly question but you have created a virtual serial port for the usb/ttl adapter. When delco (GHM) ecu programming most users had usb only laptops & had to use a usb/rs232 adapter and create virtual serial ports. Just a thought.

I have old clunker laptop with real serial port, will be building simple level translator & trying OBD II, if it fails then SSM.

Gannon · Post by **Gannon** » Wed Jan 12, 2011 9:19 pm

I wouldn't bother with OBD2, if your'e car doesnt have a 2nd oxygen sensor or the intake air temp sensor, it wont be OBD2

As for SSM, my laptop has no hardware serial ports, but with the FTDI adaptor, when i plug it in, a serial port is created in "Hardware Manager" and the software i have recognises that it is available at the serial port.

I just need to do some more testing. Maybe i need another TTL device i can try the adaptor on just to see if it is working.

magg · Post by **magg** » Wed Jan 12, 2011 10:20 pm

Another suggestion, I'm full of them, do a loop test on your usb/ttl adapter, connect tx to rx.

daza · Post by **daza** » Wed Jan 12, 2011 11:47 pm

Can you set the data rate in either "device manager" or in your software?
I don't know the rate, but was led to belive it's fairly critical?

Daza.

Suparoo wrote:I wouldn't bother with OBD2, if your'e car doesnt have a 2nd oxygen sensor or the intake air temp sensor, it wont be OBD2

As for SSM, my laptop has no hardware serial ports, but with the FTDI adaptor, when i plug it in, a serial port is created in "Hardware Manager" and the software i have recognises that it is available at the serial port.

I just need to do some more testing. Maybe i need another TTL device i can try the adaptor on just to see if it is working.

magg · Post by **magg** » Thu Jan 13, 2011 9:05 am

Another suggestion, may be the adpater need handshacking. The vwrx software uses a level translator & no handshacking. Your adapted may need it to function.

magg · Post by **magg** » Sat Jan 15, 2011 4:51 pm

Suparoo, now in your situation. Built interface to support vwrx.com ssm software but did not work & just to ice the cake my oscilloscope blow up before I could do any testing.

Will have to wait until replacement scope arrives.

Gannon · Post by **Gannon** » Sat Jan 15, 2011 5:33 pm

What interface did you build?

magg · Post by **magg** » Sat Jan 15, 2011 7:13 pm

Was similar to the "discrete device" one on vwrx.com web page. Simple level shifter, TTL to RS232 each way. Seems too simple to be true but his recommendation for his software, so worth a try.

Also, further to what daza said, have found some info on ssm protocol that says ssm uses UART settings 4800, n, 8 1. My serial port was set to 9600, probably a default setting. Don't know if vwrx software controls serial port rate, no mention in his info but will give it a try while waiting for oscilloscope. Probably next opportunity will be tomorrow.

Gannon · Post by **Gannon** » Sat Jan 15, 2011 7:34 pm

1953 is the SSM baud rate, which is rather unusual, but apparently guys have got it to work using the next closest, 1800.

I dont know if it is possible to change the baud rate to something custom?