How to read CAN bus? Is it even possible for the DIY'er?

[GTrent]

Howdy folks - here's a question for you guys.



I've searched and searched, but I haven't come up with an aftermarket way to read the CAN bus on a '01 ISB.



Anyone out there have any ideas on this? I'm trying to troubleshoot a small problem I have, but the conversion has no OBD connector, so I'm either going to have to access the bus, or take it in to the Cummins guys. I'd much rather be able to read my own codes though... ... ... .

 

[jmy]

Does your 01 ISB have a Dodge ECM on it?



If so the only CAN bus stuff is controlling the VP44 fuel system. It's identified as Cummins bus + and - from the dodge ECM.



There are interface adapters and software to acces the CAN bus here:



http://www.c-a-n.com/pccards.html?source=goog&kw=can+interface&gclid=CMa6-uTW_IgCFQFrVAodfw_YIg



However if you want to read codes, using and ODB scanner, you'll need to hook up to the ODBII/CCD bus date link connector signals.



Wiring diagram for the Dodge 01 diesel data link connector is located at 8W-30-41 in the 01 service manual. The data link connector layout is at 8W-80-27 in the manual. It's stright forward wire one. You'll only be able to access the ECM codes since you don't have the dodge PCM.

 

[GTrent]

Thanks jmy! That helps quite a bit. It still has the Dodge ECM on it, and I'm just trying to get the codes from the engine/fuel system. I'll dig through that site - thanks for posting it.



Might still be easier to hook up into the OBDII data link, I just have to trace the wires and schematics. Just one more thing on the list... .

 

[GTrent]

In doing a bit more research I found that the quickcheck system will hook directly up to the CAN bus too... . but it's pricy.

 

[jmy]

Since you have indicated that you still have the Dodge ECM the CAN bus info won't do you any good. The ODBII codes your are looking for are set and stored in the ECM. You need to wire up the Data Link Connector (as indicated in wireing diag. identified above) and use a ODB reader to access the codes.

 

[blackdodge]

Im a little late to this discussion so you may already have figured it out: but I had the same problem with my 96 suburban when I first got the 24v in it. I wired the suburbans aldl connector to the cummins ecu using the previously mentioned dodge service manual schematics (I dont have the dodge pcm) and hooked up my snap-on scanner using the key and info for 98. 5 dodge 24v and it gave me the full data stream and codes. the dodge pcm is totally unnecessary. I hope this helps.

 

[GTrent]

Howdy blackdodge, yep, that sure does help. That's basically the way I'm going to go, wiring in an OBD connector to the ECM.