I just connected pin 10 & 11 on C274 and got it to crank but not start.

I find it interesting that the ETM has sections labeled "With Theft Alarm" and "Without Theft Alarm".

 

I'll bet there is some firmware turned on in the ECU for "with".

 

Yeah, it needs to get the starter enable from the Alarm unit. you can bypass that.

There's a wire that runs from the neutral safety switch to th alarm unit. If you ground that, the starter will run. However, the ECU may still need to get the coded enable from the Alarm for the engine to run.

 

Yeah that's what I figured out. There's no "Without Theft Alarm" section for any other wire, so Buzz must be right. There's also only one other wire that goes to the ECU from the theft alarm. Like you said, it must be sending a start signal through that wire. Unless we can figure out how to disable it in the ECU, we'll have to use some sort of emulator, which is hardly better than an alarm with all its inputs disconnected.

 

An alarm with all of it's input disconnected is still going to be a problem. If it doesn't get the correct inputs it will immobilize the truck anyway.
An emulator can read the code, remember the code and send it and TELL YOU THE CODE. That way you're set for as long as the ECU lasts. The emulator won't be doing anything but sending out the correct code, regardless of what else happens. ANd if the emulator dies for some reason, you can enter the code into a new or the repaired one.

Your Viper alarm takes care of everything else.

The difference between with and without theft alarm is in the ECU or the programming of the ECU. I'm looking at that as well, but it's got two microprocessor, two EPROMS and one EEPROM. Decoding anything will be quite a bit of work.

 

I settled for disconnecting most the inputs a year ago and it's been fine since. Ideally I'd see it gone though.

I only know of one man on earth who knows how to truly disable the ECU's need for the theft alarm, Mark Adams of Tornado systems, but getting him to reply by email can be a challenge.

I really hope you're successful in this effort. What tools or methods do you plan to use to record or decode the signal from that wire?

 

I've got several Tek logic analyzers and a few Oscopes, both Tek & digital, but I'm just going to program s single chip micro to record it and then play it back at my leisure.

I'm still working on decoding both the theft alarm and the Airbag controller. Years back I knew both the Freescale 68HC05 (Theft alarm micro) and the 68HC11 ( airbag controller micro) inside out. But both of those processors are long obsolete.

I've moved to Microchip & Atmel processors, and need to brush up on my older skills as well as learn to use new tools, since the old ones are no longer made.

 

Amtel is pretty old, used those in different sizes to make PC video cards into Mac video cards back in the day. Just a flash file is all one needed and of course a decent solder station for electronics. By the way George, the Tek scopes we used at Sun Microsystems for different "things"......the best in their day. Now the military, ah the military blows the civilian toys away.... we've got some fantastic electronic diag toys.

I would mention for posterity that a few of us (99.9999%) still use our alarms so publishing this information in the clear is probably not a good thing........ so I suggest a group PM conversation. This type of information was strickly poo poo'd in the past on any LR forum, it was not cool.

 

I don't see how emulating a start code would allow one to steal an immobilized truck since you'd have to unlock it first anyways.

George, have you examined the quality of components on the engine ECU? Do they appear to be kinds that commonly fail such as aluminum electrolytic capacitors?

 

I could also add that it's not what you do see but what you don't that matters. Emulation is only one small (elusive) aspect of this conversation.......