PicoFin wrote on Dec 20
th, 2012 at 9:40pm:
Yeah, the CAN test box. Not that it would not be a useful device when you need to check the CAN bus, but how often is that? In the classes I took, they talked about the "usual CAN faults" as short to ground, short to negative, no communications, bad communications. I'm not in any way an expert on CAN, but what I've been working on has never had a CAN fault. I've seen interference in the CAN bus, but every time due to external factors. Comments on this too, please.
I think of the CAN box as a illuminated representation of the OBDII connector.
You plug it in and instantly you can see power and earth circuits are complete.I had a 2008 Holden rodeo with a common rail diesel towed in earlier in the week, crank, but no start. Connecting the scantool showed no communication. Now connect the CAN box and see the CAN signals on pins 6 & 14 missing.Cycle the ignition a couple of times and pins lit up, so it's given me a direction to head in as far as which circuit is affected.
It is also a great extension for your scantool lead allowing you to have it at the front of the vehicle or at a toolbox/work station.
Now also imagine a VW coming into your shop with a nice aftermarket radio fitted to it. You plug your scantool into it and smell a strange burning odour emitting from it and the screen goes blank... oh shit!! Thanks to a new adapter harness fitted with the stereo, it's got a 12 volt loop wire on the K line (pin 7) and has just rendered your scantool "smoked".
And my final point, who really likes being jammed in a driver's footwell on their back while trying to poke around an OBDII plug with a voltmeter hey? Here's a little thinking music while you mull it over...
http://www.youtube.com/watch?gl=AU&v=vXGhvoekY44&hl=en-GBSoooo, whatta ya think? The Pico CAN box looks pretty darn attractive now eh ?