New Tech2 Clone - am I finding new issues or causing them?

[TrybalRage]

So I'm starting a new thread as I didn't know if this was related to my original question/problem - Is my BCM bad?

I picked up a Tech2 clone from chinacardiags - first, ever since replacing my BCM I had a airbag light on that required a 'primary key reset', and I also have a P0449 code that replacing the purge solenoid and gas cap has not resolved. Plus it seems to be the general consensus here that having a Tech2 is a handy tool for our trucks. Cool.

So it finally came after a couple of weeks, and first thing I plug it in, run a bunch of DTC's and I see them pop for BCM issues, other random stuff, and I figure they may be "long term" stored since I replaced it so I just cleared everything for a fresh baseline. But it won't let me clear the P0449. Ok, we'll address that later.

I do the primary key reset, turn off ignition and back on, airbag light is off, success! I turn it off, walk away.

Come back later, connect the Tech2 - turn the key - Service 4WD, ABS, Blah Blah, error after error. Fuel gauge not showing level, Tech2 says no communications with any modules. Uh. Wut.
Try a bunch of stuff but finally disconnect the battery, reconnect, repower Tech2, Ok. Seeing a bunch of codes again for BCM, TCM, etc. Clear them all.

Try to use the special functions under the powertrain section to cycle the Evap- error, possibly wrong vehicle. Try another function - no communication. Same with others. Nothing.

If I go under 'Body' I can operate door switches, windows, and the like.

I am occasionally getting a "onstar/VCIM" error when it's establishing communications... related?

Turn off key and on again - same Service 4wd, ABS, etc errors flashing and total lack of communication with the Tech2 and any modules.

What the heck is going on?

 

[exp500]

Power your Tech2 externally. Are you wi-fi or cat5 internet?

 

[TrybalRage]

I've tried powering the Tech2 both with the cigarette lighter, and with the 110v adapter to an extension cord. Same result.

Not sure what the internet has to do with it at this point, I haven't actually connected it to a PC yet. But it would be wi-fi, although I could probably run a cat5 into the house if I needed to.

 

[TrybalRage]

After messing around some more, now I'm also getting intermittent connections to the BCM. It will work, then drop, then work, then drop....

Even when it was working, it still never communicated with my Bose Amp, which is also odd.

Modern vehicles... ugh.

 

[exp500]

You might want to poke around on a couple 75 page Tech2 posts. Some cables have been hard to fit properly without a little trimming. And many items similar to yours.

 

[TrybalRage]

Well I read a bunch about the battery needing to be fully charged and some folks having issues with it getting drawn down quickly while diagnosing. So put it on the charger overnight and took it up to full - seems to be reading ECM now and I was able to cycle the evap (or at least attempt it). I'm getting a short error displayed for the circuit in the Tech2, but the control wire at the valve is not testing to ground with a multimeter.

I did get one communication error briefly with the BCM again but then was able to do some stuff with it (just testing features out).

 

[Doubeleive]

If the battery draining is down that fast then it's probably time for a new battery
Airbag light should never come on unless the system detects a fault. I say this because the airbag will never come on unless there is fault and if the fault is corrected it will go out on it's own, yes you can "make" it go out temporarily but it will come back on until the fault is corrected. It has it's own self-check function and is not a OBD system.
evap problems are difficult the general all around fix is to shotgun it by doing all 3 (both solenoid's and canister)
connection issue's with the tech2 otherwise are usually one of two things.
1. be sure all the connections/fittings on the tech2 are snug and tight, sometimes taking it all apart putting it back together works when it gets carried around and moved around the press fit connections get loose just enough to cause problems. usually you can tell right away if it is not getting communication
2. a bad ground in the lan bus on the vehicle can cause all kinds of haywire and if that is the case it can be very hard to find.

 

[George B]

If the battery draining is down that fast then it's probably time for a new battery
Airbag light should never come on unless the system detects a fault. I say this because the airbag will never come on unless there is fault and if the fault is corrected it will go out on it's own, yes you can "make" it go out temporarily but it will come back on until the fault is corrected. It has it's own self-check function and is not a OBD system.
evap problems are difficult the general all around fix is to shotgun it by doing all 3 (both solenoid's and canister)
connection issue's with the tech2 otherwise are usually one of two things.
1. be sure all the connections/fittings on the tech2 are snug and tight, sometimes taking it all apart putting it back together works when it gets carried around and moved around the press fit connections get loose just enough to cause problems. usually you can tell right away if it is not getting communication
2. a bad ground in the lan bus on the vehicle can cause all kinds of haywire and if that is the case it can be very hard to find.

Adding a third.
Possible bad or defective VCIM in your Tech2. I had a bad one.

 

[swathdiver]

If your Suburban has the basic amplifier the Tech-2 cannot communicate with it even though it shows up. The Bose Centerpoint amplifier is more sophisticated and the Tech-2 can interact with it.

When I first got my Tech-2, the ODBII adapter was no good so I had Amazon send me one and then the place I bought it from sent another. After 5 years of near daily use, I've replaced everything but the Tech-2 at this point.

Try leaving the car connected to a battery charger since it seems like your battery is kaput.

If you go into the BCM module, then the BCM and then Charging Info or something like that, you can see the condition of the battery. Its state of charge, previous state of charge, start up state of charge, regulator set point, etc. It even calculates the battery temperature.

 

[TrybalRage]

If the battery draining is down that fast then it's probably time for a new battery
Airbag light should never come on unless the system detects a fault. I say this because the airbag will never come on unless there is fault and if the fault is corrected it will go out on it's own, yes you can "make" it go out temporarily but it will come back on until the fault is corrected. It has it's own self-check function and is not a OBD system.
evap problems are difficult the general all around fix is to shotgun it by doing all 3 (both solenoid's and canister)
connection issue's with the tech2 otherwise are usually one of two things.
1. be sure all the connections/fittings on the tech2 are snug and tight, sometimes taking it all apart putting it back together works when it gets carried around and moved around the press fit connections get loose just enough to cause problems. usually you can tell right away if it is not getting communication
2. a bad ground in the lan bus on the vehicle can cause all kinds of haywire and if that is the case it can be very hard to find.

Battery is two weeks old. It was just replaced (under warranty) and the last battery was like 9 months old. I can't seem to get this truck to hold voltage, and this might be related to my overall electrical issues. I don't drive it daily and it may sit for weeks at a time. When I drive it, park it, check voltage, it shows 12.7-ish volts. A week later it will show 12.5 or so. Another week and it will be at 12.2. I was hoping the new battery would fix that. So far parasitic draw tests (#1 pulling fuses with a multimeter in-line with the negative cable = 13mA draw well within spec; #2 current draw test across all fuses) are not showing anything wrong.

The airbag light is unrelated to my issues - I just replaced the BCM and even in the paperwork I received it gave instructions that this was normal and required a reset by a scan tool (one of the reasons I bought the tech2) and I was successful in doing this.

I was able to command the vent valve finally after charging the battery up overnight.

I followed directions posted a long time ago from @swathdiver - at the plug to the vent valve itself, I have +12v on one wire with Key on, and NO ground on the other, whether commanded by PCM or not. According to those instructions:

If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high
resistance. If the circuit tests normal, replace the ECM

So there's no short to ground, there's no voltage, so I need to trace where it goes and test whether it's open or has high resistance.

If your Suburban has the basic amplifier the Tech-2 cannot communicate with it even though it shows up. The Bose Centerpoint amplifier is more sophisticated and the Tech-2 can interact with it.

I have Bose speakers, I assumed that meant I have the Bose amp as well?

Try leaving the car connected to a battery charger since it seems like your battery is kaput.

I am doing this now as it seems to be resolving most of the communication issues, but I'm not sure why my 2nd new battery in a year keeps dropping down.

If you go into the BCM module, then the BCM and then Charging Info or something like that, you can see the condition of the battery. Its state of charge, previous state of charge, start up state of charge, regulator set point, etc. It even calculates the battery temperature.

I will take a look at this tonight.