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So I just tested the bus at the DLC, the first pic (the one without the big green wave) is when the bcm is on and working as intended, the second is when the BCM goes out and tries to come back on. I also read resistance at pins 2-4 and got 51.4 K ohms. Does it seem like the bus is shorted either way?
No, if the bus were shorted to power or ground you’d only see a line at 12 volts or ground…you would see no data packets on the scope…this is my serial data bus on my 08 with the PicoScope…also 0-7 volts.
Alright cool so no bus issue. The only issue I've seen as far as power supply at the BCM is the key reminder circuit, I'm not sure if it would have any effect on what I've got going on but checking voltage from remote ground (battery negative post) to the 2 tan key reminder wires at the BCM (circled in blue) shows 7 volts with the key in the ignition, the OE diagram of the BCM (I have it saved on my work computer, I don't have it saved at home) shows that the BCM sends 12 volts down that wire with a resistor, and the circuit is grounded when the key is removed. Again I'm not sure if that would have any effect on this situation but that is the only issue as far as power and ground I've noticed with the BCM, like I said before the BCM gets constant battery voltage feed on the supply and ignition on wires
and good ground even when it's dropping out, so I'm thinking the BCM may just be bad.
You may be correct, there are several reputable companies that specialize in repairs to automotive electronics modules, a quick internet search will reveal business like ABS Fixer, and G7 Computers.
So I just tested the bus at the DLC, the first pic (the one without the big green wave) is when the bcm is on and working as intended, the second is when the BCM goes out and tries to come back on. I also read resistance at pins 2-4 and got 51.4 K ohms. Does it seem like the bus is shorted either way?
Did you put relay 42 back in, or leave it out for this measurement?
Quick update, I finally threw a bcm in the car and it fixed my problem. It also fixed my starter issue so that's cool. I appreciate all of the answers and help, Definitely helped narrow it down.
