Does anybody have any idea what this is? Found out today that my truck won't start without it plugged in and I can't find it searching online.

The only identification is the gold lettering saying silencer.


https://lh5.googleusercontent.com/-P...1/silencer.JPG

 

A friend of mine wondered if it might be an aftermarket security device that cuts power if removed so that it can't be stolen.

 

Looks after market to me.

 

That did not come from the factory. I've never seen anything like that on all the DII's I've parted.

 

I bet your friend is right, which seems very stupid to me because now how int he hell you do diagnosis a run problem with a live data scanner?
If the engine wont run without that thing in place you (or a shop) cant plug into the OBDII port, hook upto the scanner and watch the engine run, which is very helpful when trying to find problems.

I would find a shop that installs those kind of car security things and have it removed.

 

Your ECU has probably been re-chipped to include the security device...

So, In order to get rid of it.. You're going to have to restore the factory chip and settings...
Good Luck...

 

I have seen these devices added as security/kill switches, but never through the ODB-II port.

 

If that is the case then a different ECU would take care of it right?

 

First, do you really think that thing plugs into the OBD port? It doesn't look anything like the multi pin plug required for OBDII. Did Bryan actually say it plugged into the OBD port?

Second, I think that's a fairly simple interrupt switch. Certainly nothing as sophisticated as requiring a chip in the EFI ECU or BCU.

Third, should anyone ever actually need to swap EFI ECU's without using textbook, they must also swap the matching BCU. Just putting a different EFI ECU in may work in very rare and lucky situations but more often it's going to mean a tow to the dealer.

Just my 2 cents.

 

I found this:

https://www.cesupply.com/MagPublic/P...5900PKP_UM.pdf

It's a PDF about Silencer alarms.