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Well, I'm still at it...
ok, I've gone through ALL the modules I can find. What I couldn't get to/didn't have were the Amplifier-Radio Mod, Hands-Free Mod, and the Satellite receiver Mod. I don't think I have those. I looked where they were supposed to be and nothing.
I unplugged each module as I found them and no change to the CAN system that I can tell. Unable to read with a computer scanner and no PRNDL lights coming on either.
I'm getting stuck right now. Does anyone know a good way to test the TIPM or the PCM without a scope? Those are the last two that I can't really check. They are also the modules that I've already replaced...
Thoughts?
So, I still can't get the vehicle to start, but have made some progress. The ECU and TIPM are ok - that's been verified. I have perfect resistance now (60 at the OBD2). What I just found out is that my CAN High and Low are both reading 2.4 volts. What I don't know is how I can check to find out where the problem is. I'm guessing that there is either a short in another module (I've replaced many of the modules already) or a short in the wire itself. Any thoughts on what I should be checking next? I feel I'm very close to figuring this out.
I do think that they are shorted together. I'm using a Launch Code Reader (the $300 dollar one) and It still does not detect the ECU or PCM, BUT it does find the SRS system. When I check the SRS it tells me which modules it is having a problem communicating with because I had them unplugged. When I plug those modules (i.e. overhead, radio, and console), the errors go away. I think those modules are working ok. So the problem that I'm trying to figure out is how I can find the short between the CAN Hi and Lo. Any advice? I can't find anything about how to do it online and I am lost right now. I'm thinking it is the wiring to the ECU/PCM (one unit), but I don't know what wires to probe or if I should be testing voltage or resistence, etc. Thoughts?
IT RUNS!
So I was looking at wiring diagrams and getting help from people (Thanks Scott!). We noticed that the ECU and TIPM were fried and on the same CAN C BUS. All other modules that were ok were on a different CAN. I searched for the ABS module which was the 3rd and last module on that CAN. I unplugged it and the truck started right away. After almost 1.5 years, it's running just like it was, but without ABS. I have to get my hands on a new module. Thanks for all the help everyone and I've learned so much more than I ever thought I would have needed to know about repairing the electronics on a vehicle.
