Security system not active

Did it ever work as you think it should?

 

How are you unlocking or opening the door when you test this?

 

You probably need to contact the company that made the aftermarket alarm.
Many of them are not intended to interface with the car for audible alerts and have their own horn.

 

Yes, that seems like a malfunction. My Gen 3 with the basic stock alarm system, no aftermarket changes, would alarm in that scenario.

Do you have access to your repair manual and wiring diagram (more info)?

 

“Q: Did it ever work as you think it should?

A: No, it has not.”



No, it has not.”


In that case, I would suggest that it should be considered a completely separate aftermarket system for troubleshooting purposes.

 

i think the problem is 'salvage vehicle'. wiring could be an issue somewhere, not likely something anyone else has experienced in the same way/place

 

a bad ecu should throw a code i would imagine, and even faulty wiring in many cases.

google might help find a wiring schematic if available, otherwise, you need 'techinfo.toyota.com'

 

It certainly doesn't come up very often........if at all.
And details like that aren't usually widely published in an attempt to keep the information out of the hands of thieves.

 

This sounds, offhand, like it falls in that category of "issues that don't arise in a typical Prius under normal conditions". In other words, issues that are probably secondary to the car getting modified in some way—whether that was by someone's deliberate rewiring, or occurred in a crash or some kind of rodent or environmental damage or the subsequent repair.

The thing about issues in that category is that you often don't get a lot of people chiming in with "oh yeah, that exact thing happened to mine" because it probably didn't. Those weird issues that are secondary to something weird that was done to the car come in as many flavors as there are weird things that happen to cars.

That doesn't mean they have to be hard to troubleshoot. You just need to fix yourself up with a meter and the wiring diagram and start working it down.

Thinking about the typical odds can help here. ECUs are solid state with no moving parts, and they fail a tiny bit more often than rocks do, but not by much. In pretty much any of the troubleshooting sequences you find in the repair manual, "ok, must be the ECU then" is the step that comes after ruling out every other possibility. In most cases it's perfectly reasonable to start by asking the ECU what it thinks is going on; what it tells you will usually be useful even when it's not the whole story.

I've been through nightmarish bad-grounds problems in older vehicles (often beginning when the body sheet metal serving as ground was severely rusted away). A Prius has a lot of ground points though, at different spots on the body and bridged by wires in the wire harness; it's a fairly redundant setup.

If this car were mine, I would probably start with the wiring diagram and carefully compare what's in the car to it, and see if I could spot any differences that could be the results of aftermarket alarm installation, or of salvage-vehicle repairs.

The great thing about knowing where the wiring diagram is is that you've got the "I wonder where the components to X are" question covered no matter what X is, and it saves you having to walk around with 400 pages of diagram somehow committed to memory.

This wiki page that Elektroingenieur put in the work to compile will show you a lot of the ways that you have access to the repair manuals and wiring diagram.