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GODIAG GT100+ test drive

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13 Sep 2021 13:58 - 13 Sep 2021 14:43 #51401 by Tyler
GODIAG GT100+ test drive was created by Tyler
Most of the regulars know I'm a big fan of the original GT100:


It's not one of those things that you need daily? But man you want one when you need one. :lol: Anyone that's gone to war with a network/no com issue knows. Life is too short to go poking DLC pins under the dash.

So, when GODIAG offered to send me a sample of their upgraded version, I sat up and paid attention:


The GT100+ looks very similar to the original GT100, with one big addition - the ammeter. This is specifically aimed at anyone using the GT100+ for bench testing or programming. Let me explain.

Like the GT100, the GT100+ comes with a breakout harness for supplying power, ground and communication to a module:


I know, it looks like a disaster. :silly: But it's actually pretty easy to get a module hooked up once you get familiar. Each pin is clearly labeled, and there's usually enough powers/grounds to most anything you're gonna connect to. Only really needy modules (think GM BCMs) require additional pins. The pins themselves come in two varieties, and work perfectly for connecting up to the common sizes of male pins you find on modules.

As an example, I've got a Ford manual HVAC module on the operating table. One power, one ground, two MS-CAN lines. No problem for the GT100+:


But am I connected correctly? All my pins are there, but it's not drawing any current. :unsure:


Whoops, counted one pin too far! Let's try again:


Now I know I got it right. B) The module is now drawing 30mA. That's the value of the ammeter - confidence in your setup. If you're not drawing current, recheck your connections. If you're positive you're connected correctly, then the module itself is suspect. 

So how accurate is the voltmeter and ammeter? I checked the indicated voltage against my Owon B35T+:


Surprisingly accurate. Then I checked current draw with a 7442NA bulb to put a bit of load on the internals:


Close enough for me! That then begs the question, how much current can the GT100+ supply? It's not stated in the user manual, but the engineers tell me 3.0A:

It is a self-recovery protection, short-circuit automatic power-off protection. When the current comes back to normal, it automatically resumes normal operation.

I'm no engineer, but that sure sounds like a PTC thermistor to me. :silly: But let's put it to the test. I connected up an H9 headlight in place of the 7442. The in-rush current will exceed 3.0A.


I couldn't catch it on camera, but the whole interface goes dead when first connected.  After a few seconds, the GT100+ recovers and does its level best to light the bulb. The voltage reading backs up my PTC thermistor theory. I repeated this several times just to see if I could let the smoke out.  Couldn't kill it! 100% knuckledragging ape-proof.

So, you've already got a GT100. Should you upgrade? :huh: That'd depend on how much bench testing and programming you do, or if you'd like to start. The ammeter isn't connected to the OBD cables, only the ECU breakout, so it won't function while using the GT100+ as a memory saver (which is a nice feature by itself).

If you're considering a breakout box, the GT100+ should be high on your list of candidates. You can't build one yourself for much cheaper - I've tried. :lol: And you'll be hard pressed to find another BoB with the same features.
Last edit: 13 Sep 2021 14:43 by Tyler.
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13 Sep 2021 21:04 #51409 by AJeep18
Replied by AJeep18 on topic GODIAG GT100+ test drive
Well now I'm glad I hadn't bought one yet!

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14 Sep 2021 08:34 #51414 by Chad
Replied by Chad on topic GODIAG GT100+ test drive
That looks like a very handy BOB.  I just ordered one.

"Knowledge is a weapon. Arm yourself, well, before going to do battle."
"Understanding a question is half an answer."

I have learned more by being wrong, than I have by being right. :)
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16 Sep 2021 18:06 #51500 by juergen.scholl
Replied by juergen.scholl on topic GODIAG GT100+ test drive
For those of us who already own the original GT 100 you can externally wire in this type of volt/ampmeter or swap it with the original one. These meters are CHEAP.


An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
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