Troubleshooting Suggestions?

[Pilkerton]

So after requiring an unplug/replug cycle to operate for a few days at a time, my BlueSaab unit finally stopped functioning a few months back. The symptom: it paired just fine, but never showed up as 'CD1' in the head unit.

Since it got progressively worse before dying altogether, I suspected a hard component fault on the PCB. But swapping out the CAN controller and I/F chips (and updating to firmware 3.7) did not help.

Something very weird did happen one time I plugged it in: the engine fan came on (!) full blast. The car had been sitting for hours and the engine was definitely cold. Unplugging/replugging the BlueSaab unit caused the engine fan to shut off.

So what are a few things I can try?
Is there anything like a loopback test that's possible?
Or is another BlueSaab (or a 2nd Arduino CAN adapter) required for me to test it out-of-circuit?
Where does the CDC cable in the trunk go to? Could the cable be damaged somewhere?

Also I noticed that both the mauselec and Spark Fun CAN adapter designs include zeners and either an L or RC network on the CAN connections. Shouldn't BlueSaab have those also?

[Seth]

I recently had a v5 module sort of do the same thing for no reason; just stopped responding (can lights go solid as soon as i plugged it in). idfk...

the module talks via the iBus, so maybe it was spitting garbage out and the car didn't like it and somehow triggered the fan; i know that when doing an ECU flash, the fan will go full blast, and eventually requires the ecu fuse to be pulled to reset the system to finish the flash. sounds similar...

the new v5 pcb does have an ESD diode on both lines, but that's just for ESD protection. The inductors aren't necessary, and the pulldowns via caps are prob for ac coupling or something. i haven't had any chips go bad (that i know of) so I don't think it needs anything else but who knows.

there isn't a loopback test, but that would be great to implement (cough, cough, *karlis*, cough ;)

[Karlis]

O-oh!

The only time I've seen engine fan go off at full speed is when I was messing around with custom SID text control and screwed up a bunch of things causing buffer overflows and what not.

You said you upgraded to v3.7 of the software. I would suggest you upgrade to 4.0b. Yes, the latest beta turns out to be the most stable software as of now. I know for sure it fixes two nasty bugs. One with CAN comms and the other with a frame length of 3C8 (CDC status report).

At the moment I suspect there's more we could do with MCP2515 CAN chip to handle situations like these. I'm working on this guys...I'm working... :)

[Karlis]

Having had another look at my notes from way back, this issue looks very familiar to one I've seen before. For some reason 328 went into a bizarre mode and started to dump lot's of stuff on the bus eventually locking(?) it up. Had to pull the fuse to remedy the situation...