OBD II - testing for it's presence?

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For my 2003 Pulsar, I have the OBD connector located, and have after many days of searching deduced that the connector supports a combination of "DDL1", "DDL2" and ISO9141.
DDL1 & DDL2 appear to be Nissan's Consult II type system for CAN network.

Figuring that I didn't want to invent an invented wheel with the OBDuino, I ordered and tested an ELM327 adapter on the plug - the adapter works in that when I open a screen session to the adapter, I can see it's Querying and Unable to connect.

It pointed to it's inability to speak to the ECU basically. So I looked up the pins, and figuring it might be something to do with CAN network, I cut the wires in the ELM327 to only have the required ISO9141 pins, 4,5,7, and 16. My car doesn't have a pin in 15 - which seems normal.

However, no joy there, I opened a screen session, sent 01 01, and still same result.

I kept searching, found that the ELM327 might not work with Nissan's Sentra 1.8 2003 - I think it might equate to Nissan's Pulsar. I also found Nissan Sunny N16 doesn't work - again, similar to the Pulsar.

So, I think the ELM327 is at fault.

But I have the arduino - and already ordered the SI9243 chip (still waiting on this though). What worries me is that I might not be able to get OBD II Communication if it's not implemented - how can I test for this in a simpler manner?

CAN communication might be another possibility (and would be better in terms of speed), and I note there is an OBDuino setup using "CAN".

I've googled around to see if perhaps, another ecomodder has come across it but then I figured it would be less likely as the overwhelming members are US- which is legislated to support OBD II.

Any tips on how I can be sure it's just the ELM327 that's the issue? Perhaps some way of interfacing the K-Line to the arduino and getting garbage data ?

[Cowboy_Dan]

Check the voltage from ground to the CAN HI and CAN LO pins (6 & 14 for U.S.). It should be about 2.5 volts on each with the key on and at least one device broadcasting.
If you have those voltages, then you know for sure there is some sort of messaging going on there.

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Ahh, I don't have pins in 6 & 14 - the pins would be 12 & 13, as these have descriptions of ABS and SRS airbag with TX / RX - I don't know for sure if they are in fact CAN - but it gives me an avenue to test with (2.5V on 12 & 13 could be that Nissan Consult II is also "CAN") - or it could not.

[Cowboy_Dan]

If pins 12 & 13 are called out by Nissan as Tx and Rx, then I extremely doubt that they are CAN. I have yet to run across a schematic with the CAN wires labeled as Tx and Rx.

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I meant to update!

Pin 12 & 13 are described as TX / RX for Nissan Consult I protocol, which was previously used as OBD connections, but now doesn't talk to the ECU, just perhaps, ABS, SRS.

ECU is on Pin 7 apparently, and would either be Consult II & OBD II, or just Consult II.

I'm keen on chasing out the ECU pins, I'm hopeful I'll find a CAN across there somewhere, whether that'll help make an OBDuino or not is another story.

Consult II doesn't have as much info as Consult I in terms of protocol. OBDII didn't seem to work with the ELM327 cable. CAN is mentioned as being in the 2003 model Sentra's, and my VIN coincides with what I think is the Sentra VIN. Sentra being the US market - Pulsar being Australian. I thought Nissan Sunny would be it.

I'm really avoiding the urge to just go at the injectors and setup an MPGuino instead. I *hope* I can find CAN lines at the ECU - if that helps make an OBDuino I'll be unsure.