Can you use old-school ways to fight new-school tech?

TheBac

Why do I keep doing this?
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Apr 19, 2008
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I dont know jack about this, so I figured Id ask. I think you'll get the jist of what Im trying to do. If Ben were still around, I could bounce ideas off him, but he's not, so I can't.


So, hypothetically, how would someone go about using a resistor(s) to simulate a module to the ECM in order to remove said module?
Where/how does one measure the resistance? Unplug the module and measure across the module terminals with an ohmmeter?
I figure GM uses the 5volt system to report module health? When something is "healthy" or working correctly it reports 5 volts, and lower volts when its not?
How does one work around canbus protocols? Ive found canbus emulators online for large truck systems, but not sure if they'd work on smaller trucks/cars.

Im asking b/c I didnt make a trip to Oz in time, and my options for my Cruze are limited now. Sucks, but it is what it is.
I dont care about the exhaust itself, that system works fine so far. I just replaced all its sensors so it should work fine for a while.

But, I would like to remove the hardware in the spare tire well, so I can put my spare tire there.....if you get my meaning. That system doesnt work worth a hoot. Constant messages about fluid quality/reduction in speed after 99 miles and such. Just spent $300 to have more work done and ECM updated, but I dont trust it. Id rather lighten the car, if possible.


Like this: https://www.myturbodiesel.com/threads/hacking-the-injection.24641/
 
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2004LB7

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Dec 15, 2010
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Traditionally many of the sensors where analog and could be tricked. There was often times just a two wire sensor which was either just an on/off switch and variable resistance ones. The problem with those is they are dependent on the resistance of the wires and connectors plus the voltage sent to the sensor. This causes accuracy issues. Thus the three wire sensor. One for a voltage supply (5 volts are common) a ground for a reference and a signal wire. This allows the sensors to basically send a relatively consistent signal even without the best of resistance in the wires, connectors, etc.

Taking this a step further and some of the sensors where starting to employ regulators in the circuitry by drawing off the supply voltage and ground. Then sending off a consistent signal. But as data got more complicated and accuracy needed to improve they went digital by sending (usually) PWM- pulse width modulation or frequency modulation, the MAF sensor is a good example of a frequency based sensor. From this the resistance of the wire was not as important. As long as the pulse was readable the data was good

The first generation where quite easy to trick. Either a switch for the on/off style. A potentiometer for the three wire (ground and voltage to the outside terminals and signal to the center terminal or wiper pin. This sometimes works for the regulated ones too if the ecm/pcm is not too picky about the data. The next type is much more involved with 555 timer chips or other circuits to mimic the desire signal.

Another thing to add is many times with the more modern ECM/PCMs is they are also expecting a certain value from the sensor and if it is not correct then CEL. This would be something like the fuel level sender always being the same value for over a set distance. Or an O2 sensor not changing when the fuel ratio changes or when cold vs hot

If you have a particular sensor you want to mimic then let us know and we will figure it out:D
 

2004LB7

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Ok, reading your question again, I think I know what you want

I think you will need something more then a resistor for that. You will likely have one or more sensors under the car that will need to be faked plus the pump, heater if it has one and maybe a level sensor. The ones under the vehicle will be the most important and likely the hardest to replicate
 

02greysixer

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Jun 4, 2011
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I think the pump and heater might be able to be fooled. Maybe. I dont see how you could fool a NOx sensor. ECM is expecting to see different values from each one based on throttle position, EGR position, engine load ect. If you somehow were able to mimic a happy NOx reading for highway speeds as soon as you were idling in traffic the ECM would know something was up

Sent from my SM-G960U using Tapatalk
 

TheBac

Why do I keep doing this?
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Apr 19, 2008
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The tank- and line- heater circuits come off the GPCM, if you can believe that. IIRC, they were simple +/- with no canbus.
The pump control has connections to the ECM and GPCM. Pressure sensor and purge valve come off the ECM. All have canbus circuits to them.
I didnt think that the NOx sensors would have to be dealt with. Ugh.
I just dont understand how the high/low circuits and such work. Wish I wasnt such a dummy to this stuff.
 

clrussell

pro-procrastinator
Sep 23, 2013
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Is there no one else out there that does what you’re wanting? I haven’t read up on Cruze stuff recently.
 

036.6turbo

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Jan 17, 2014
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I guess my question is, why can't we talk openly about it? Is it a concern that the government goons will see this platform as promoting illegal activities or is it something else?

This may be the wrong place to ask, but I am curious.

With the crack down, I really kind of thought these activities would revert back to the old days, when there were sub forums dedicated to these things, info was shared. Back before it became big business to....

I probably think too much.
 

KyleC4

Tech
Dec 30, 2016
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Honestly I don’t believe this is possible without serious work. I believe just in that system there are 3 level sensors, a pressure sensor, and 3 heaters and much more. But even if you tried to fool the system you’d need some kind of rotary switch to vary resistance. Because as the system commands certain functions it will be looking for a change as well over a predetermined period of time. Ex, if the car commanded the system to be used and it never sees the level sensors change, it’ll set a fault thinking the sensors are faulty.
 

2004LB7

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Dec 15, 2010
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I guess my question is, why can't we talk openly about it? Is it a concern that the government goons will see this platform as promoting illegal activities or is it something else?

This may be the wrong place to ask, but I am curious.

With the crack down, I really kind of thought these activities would revert back to the old days, when there were sub forums dedicated to these things, info was shared. Back before it became big business to....

I probably think too much.

It's not really about the guberment watching us or anything like that. Its more along the lines of not promoting illegal activities. There are many who come on here just to ask how to disable the EGR or gut a DPF. They either get there answer or not but never come back.

Some may even be agents or paid by the epa/carb, etc to test us. Find out who is provided these services so they know who to take down next. It is unlikely they can stop a discussion board but they can stop a vendor of said activities.

So in short, it is a touchy subject. And something you have to be careful with
 

DPC

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Jan 2, 2012
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I had a 2014 Cruze and used EFILive to tune the car. Is this option no longer available?? Wrecked the car a few years ago and haven't messed with cruze tuning since...
 

TheBac

Why do I keep doing this?
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Apr 19, 2008
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I thought you couldnt pull the base tune out of the 14-15's, like the LMLs are. Have to admit Ive never tried.
 

TheBac

Why do I keep doing this?
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Apr 19, 2008
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Oh hell, I had no idea Snipsey had open-sourced the stock tune. I'll have to download that and give it a shot. Thanks!
 

Benny315

Benny
Feb 11, 2019
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Some more read for you.. That nox sensor almost sound similar to an o2 sensor.. Can you trick it like a o2 sensor, I don't know but sounds possible.. Trial and error. https://www.searchautoparts.com/mot...-repair/diesel-nox-sensor-technology?page=0,0 And then found someone is making a 6 wire bypass but have not read up on it. http://brandnewwire.com/scr_adblue_..._6wire_for_mercedes_bluetec_cars_and_vans.htm There looks to be alot of read about the system. Can you just cover the sensor so it doesn't "smell" but still feels the "heat" like an 02 and get away with it, I wounder..