No CE light coming on/ no OBD connectivity

[Michael Lambert]

I have a 03 Silverado 2500HD 6.0L.  My original issue started when I went through a rough patch of road.  My truck stalled at 3,000 rpm and would not start right up  After about 10 min the truck would start but would not go over 3,000 before the light would start flashing and the engine would start stalling.  Happened 2 more times before the tow truck came.  Got the truck home and it started up on the tow truck and backed it out. Did the stall issue again with hopes of recording the code when it completely died and would not start up again.  I lost all accessory control and had ABS, power red message, and airbag message.  The security light would stay on and I would not have the CE light appear at all.  Eventually with tinkering I was able to get the CE light to appear and the truck would attempt to start but sounds like I have 2 bad batteries (both are continually on chargers and metering around 12.5-12.8 V). Eventually it would go back into the screwy mode and I'll lose window, lock, etc.  I've replaced the starter and ignition switch,  cleaned and reattached the motor and frame grounds, pulled the fuse box cleaned/inspected wires, all fuses are good and relay swapped and working.  After the ignition switch was replaced I was able to reprogram the security and got the light back and pulled a P1518 code.  The truck tried to start again but did not sound like it was getting enough volts and I got all window,lock,etc controls back.  I'm now back to no CE light (no OBD communication) and the security light back on.  Is the BCM not communication with the vehicle? 

[silveradosid]

look under drivers door at the front cab mount, there are ground connections there that might need to be cleaned and reconnected

[tlaw91]

P1518 is a bad throttle body connector, we always sell the throttle body as well. That can absolutely cause a crank no start


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