Nixer

PYROFUSE
Porsche P/N: 958 611 205 00
VW P/N:4G0915519

Nixer

Not sure if there is a reset switch in the newer cars. I read online that older cars had an yellow reset switch after pyro switch activation..

69gaugeman

If you jump the two terminals and it works fine, it has to be the fuse that's the problem. What is the resistance across the fuse when it is out of the car?

CAVU

Okay. Here is my theory, which is a repeat of an earlier idea that we have been talking about.

Your new pyrofuse and power distro box are probably just fine. Compare the resistance between the hacked on one and the new one.

The external connector (squib connector) with two pins that locks into the purple connector is the pathway for the electrical signal to fire the pyro fuse.

The pyrofuse and squib connector are dumb.

When the airbag was commanded to fire, a "crash" message was sent into the cars communications system and then the Control Unit in charge of listening, recording and reacting to many events including "crash" heard it and sent an electrical charge down to the pyrofuse through the squib connector and bang, it's done. When I looked at 991 VAL with its 82 pages, there was a Item for Pyrofuse status and about 10-12 crash status entries.

So, the Control Unit has a BIT or multiple BITs set to "no freaking way are you going to start the car normally". Until that BIT, and possibly others, are reset to "everything is good" you will not be able to start via the normal new profuse, unless the pyrofuse is sending a signal that it is bad, depsite being new.

How far away is the dealer from you? Go by and visit with them.

Nixer

I tested the pyro fuse and it's no good.

It has a resistance of 1 which means it's not working. The fuse has a blue tab on the back and I peeled it off to see what's inside.. I guess that's where the fuse link was it must have gone off when I connected power. But why is it happening with the new distributor and fuse???
See the pics.



I am wondering if the car has some fault codes stored which is setting the fuse off. I wouldn't know until I get another good relay and put it on.





The nearest dealer is 40 miles away. I have to get the car towed. I am also working on some body parts.. so can't really take it to them yet. I went ahead and ordered a new fuse link ... $107. It takes them 5 days to get it. Can't do anything until then.

CAVU

I am thinking that because the Pyrofuse BIT is set to "fire" in the Control Module that there is a constant voltage down that squib connector.

Don't install the new pyrofuse until the dealer has a chance to advice you. I suspect you can reinstall that hack job, drive it up there for them to reset the code unless your durametric idea works. That's a safety thing and my guess durametric will not let you touch the safety soft switches/BITS.

Nixer

I put the hack back and ordering durametric tomorrow. And yes, I am planning to take the car to the dealer if durametric can't help. I can't figure out what energizes the squib connector. It still gets power to blow the fuse off...

CAVU

I suspect that one or several things are driving the constant volts (12v ? you can measure it easily) down the squib connector:

- PYROFUSE Status is something other than "OK" so the Control Unit is sending voltage down the line

- Event Crash type diagnosis is no longer "No crash" and but the Control Unit that recorded the crash is still set and passing it to the control unit that is setting the PYROFUSE Status to fire.

- Airbag might have been replaced, but the Control Unit that recorded the firing are still set and passing it to the control unit that is setting the PYROFUSE Status to fire.

Nixer

It reads 0.02v between the terminals on the squib connector.

I didn't check the fuse status before putting the new distributor on. I got it from someone locally that claimed that the distributor was new and never used....probably the fuse was bad in it... there is only one way to find out.

CAVU

That voltage reading is good info and i presume that you had the hack jumper connected. That might be good news overall but at that expense, but your going to the dealer for a PWIS post crash reset is a good idea.

I think your guess is a good one that the pyrofuse was already blown before you got it. I bet it is not odor free or silent when it fires.

Nixer

5 days to get the pyrofuse from the dealer. I am surprised that I was able to order it through the dealer. I hope it won't go off again when I put it on. Will clear all the codes with durametric first and try it. Keeping fingers crossed. Also thinking about a piwis 2 tester. Even Chinese knockoff units are around $1500.

JaredT

Sorry to bring this back from the dead, but I was wondering if this issue was fixed, and what was learned from it?

Nixer

Yes, the issue was fixed by replacing the power distribution box in the battery compartment. The fuse was blown but the fuse can't be purchased separately so i had to buy the complete distribution box and replace it.

CAVU

Thanks for the closeout on your experience. Enjoy the ride!

dan 64

Hello if you would be able to help me out that would be great im having the same issue thanks. what codes did you have and did you earse them before putting in the new parts and was the durametric tool helpful