Tacho troubleshooting on C12 CAT

[Aussiecoach]

Hi

I was hoping someone could give me some pointers on trouble shooting a tacho on an early CAT C12?
What would I look for when testing with a multimeter and would the connection be on the engine or alternator?
Thanx Glen

[luvrbus]

The tach signal comes from the ECM I think it's pin J1-38 on the non Acert 70 pin connector for the 120 pin I will have to do a little research

good luck

[Aussiecoach]

thanx for that Luvrbus
Would I just be looking for a pulsing voltage on that and would I damage anything by testing for a voltage with a multimeter to earth?

tahnx
glen

[luvrbus]

I don't how you would do that with a multimeter the best way is with the software

good luck

[Oonrahnjay]

I don't how you would do that with a multimeter the best way is with the software
good luck   

      I think that Clifford didn't spell that right -- it should be $$$$oftware!   But what cha gonna do. 

      On a more serious note, I bought some software from a vendor who had hacked the computer programming for VW/Audi vehicles for use on my VW TDI.  It works like a charm and comes with an OBD interface connector cable.  It cost about $240 (if I remember right) and does just about everything that the dealer software will do (in terms of both reading stored codes and also setting variable parameters).  It's been pretty much perfect.  I understand that you can buy the "real" software from VW/Audi but they want like $5995 for it.  Have NO idea what DD or Cat or Cummins or IH wants for their software packages.

[bronson]

 I have little experience with the c-12 but it looks like the ecm relys on a signal from cam sensor and crank sensor. Best way as luvrbus stated is with a scan tool to see if you have a signal from each. See attached description of circuit. Hope that helps

[luvrbus]

Cat is not that bad Bruce they sell it for around 1000 bucks or rent to you most Cat mobile service guys have it on the service truck and if they have time will scan it free 

[Oonrahnjay]

Cat is not that bad Bruce they sell it for around 1000 bucks or rent to you most Cat mobile service guys have it on the service truck and if they have time will scan it free 

     Glad to hear that.  That's pretty helpful in a practical way -- it's kind of a shame when that's what you DON'T expect, isn't it?

[Aussiecoach]

Thanx for the replies all very helpful
I was thinking of getting the PC version of the Silverleaf do you think this would help with this?
Now all I need to do is find a Silverleaf seller that will ship to Australia as there is no agent here.
I have some douts as to weather it will read much as I downloaded the program and it doesn't appear to have the 410HP C12 as an engine option.
Thanx Glen

[Boomer]

You can buy it direct from Silverleaf, I always have.  They are good guys, give them a call.  Or you can contact Jim Sheppard (RV Safety Man) on the bus forum here or Eagle forum, Jim is a distributor, also a good guy.