I think I killed my PIU

[Neitron]

In the process of trying to get the horn working, I shorted something and now the car wont do anything, almost.

I thought I was about to make the horn sound, but instead I got a spark and the wire was welded to the frame. followed by everything going off and no activity when i turn the key to any of the positions.

What works: the power locks, the radio / no display, the lights inside and out, power seats, and power port.

What doesn't: any action from inserting or turning the key, displays both drivers and middle, HVAC (no activity).

I have pulled the neg off battery (nothing new), checked all fuses under hood (all good), and fuse22 horn (and good).

I believe I had the lead on the purple/green wire coming out of the BCM, but pulled it out before I thought about confirming the placement, when the wire shorted and "I lost everything"

I'm looking for any suggestions before I dive under the dash to check fuses in 16 degree car.

Note: I have FORscan but only used it once and saved the information to tablet. Now i'm not sure when i connect it if I am looking at the current car settings or if it is reverting back to the saved file. So, I do have FORscan as a tool if it will help in diagnoses.

 

[jmr061]

Sounds like you fried the BCM. What pin did you short on the BCM? Do you even know for sure. That would be helpful information.

 

[Neitron]

UPDATE:
I believe I stuck the probe in pin 33 of C2280B, but I can't be positive.

Hooked up FORScan and got errors in PCM, GFM, OCS, ABS, RCM, and PSCM, but unable to read DTC.
The BCM and IPC don't have any errors. While I had FORScan hooked up, I was able to enable Remote Keyless entry, but I haven't added the remotes yet. so I'm thinking that the BCM is working ok which then gives me a bigger question mark as to what is wrong.

 

[kobresia]

I'd start checking fuses, starting with the ignition switch fuse (#28 in the cabin box).

I'm not sure because I haven't actually tried this, but can you perhaps "talk" to some modules with the ignition off (or non-functional), namely the ones which control functions which remain live when you turn the key off? I could see things which are off when the key is off probably would throw errors because they don't have any power and can't be talked to, so their codes also couldn't be read for that reason. All the modules you mention having faults sound like things that probably are only live with the key on.

One way to check would be to see if you can still access the BCM and IPC with the key off. I'm guessing the IPC stays somewhat live with the key off, for the user parameters which are set through the menus to be accessible to the other modules, the BCM controls numerous things which remain live with the ignition off.

I'd play around with this myself to satisfy my curiosity, but I've already spent a considerable amount of time in the past few days, fooling around module programming, flipping different bits to deduce functions between my non-SYNC PIU and a wrecked one equipped with SYNC that I'm scrapping.

 

[Neitron]

Thank You kobresia, the ignition switch fuse was blown. Replaced the fuse and the car started.

I now have the ABS lights on and the display says that the Traction control is off. FOScan says lost communication with braking module.

I have a busy morning but should be able to look deeper this evening.