Tech 2...

Hey swath....can you answer a question that I posted here?
http://www.tahoeyukonforum.com/threads/finally-ordered-a-tech2-need-help.98343/

A question regarding the Tech 2 scanner.
What functions can it perform with a vehicle that doesn't run?
You may recall Swath, the thread about my 06 Tahoe that has a no start, no crank, no anything problem. Would a Tech 2 allow a look into the PCM to see what isn't connected? Vis a vis, a missing ground or other incomplete circuit? Would it read codes if the battery has been removed and replaced? (Something my simple code reader can't do)
Thanks in advance.

I think so but don't know for sure, never tried it on a dead car. If you were to try it though, for starters, you'd have to power the Tech2 from an external source, either directly off a battery or maybe from one of those emergency car charger/jumpers with the clips or cigar lighter adapter.

Try to download a manual for the Tech2 or GM service manual for the vehicle in question. You could also pose this question to a fella on youtube who makes Tech2 videos. A quick search should locate him.

Happy Thanksgiving!

You are going to need to apply power to the vehicle's computer. The Tech 2 gets its power from the OBDII port. (You can power the unit via AC, but that is for when you are doing programming and have it connected to a PC and situations like that.)

Once you have applied power to the vehicle, it should be able to show you what has been saved. To your question, it will not be able to tell you about grounds and things like that directly (It does NOT report back "Pin 19 - no power" or anything like that.). You need to perform tests of some systems and infer from the results. You should be able to run electrical tests on modules and whatnot (open/close actuators, etc.). Obviously you can't see any live data from the engine if it is not running.

Hope this helps.

Most of the vehicle electrics are still working.
Interestingly, the ignition switch, when turned to the "on" position will now allow the windows to operate, the gauges to come alive and the heater to work whereas before, none of this was possible. That result is through no effort on my part.
That said, I would think that the ALDL is active. Easy enough to test I suppose.
And if the Tech 2 will allow me to operate devices as you describe, that's the kind of tool I'm looking for.
(For the record, I'm an industrial automation electrician. Robots and servos and equipment like that. But troubleshooting a modern vehicle without tools or drawings? Forget about it!)
Thanks for the input.

Lots of servos in these trucks!

swathdiver said:

Lots of servos in these trucks!

Click to expand...

There are a few I can think right off the top.
And the PCM is not unlike a PLC. Just like a PLC you need the hardware and software to have a look inside....

How is this working for you?
Did you need to order anything over and above what comes with the scanner?
I have a 2006 that I'll be attempting this on.

(posted over at this thread too)
http://www.tahoeyukonforum.com/threads/finally-ordered-a-tech2-need-help.98343/page-2

Now go to ebay and look up "seriousctbuyer" and ask him if he has the service manual on cd/dvd for your truck. Might even have downloadable version too. My cd was missing the Magna Power transfer case but he sent it over right away via email. Everything is in pdf form.

Now once you have the codes and information the TECH2 sees, you can look in the manual and see how to fix it!

Alberta Tahoe said:

Most of the vehicle electrics are still working.
Interestingly, the ignition switch, when turned to the "on" position will now allow the windows to operate, the gauges to come alive and the heater to work whereas before, none of this was possible. That result is through no effort on my part.
That said, I would think that the ALDL is active. Easy enough to test I suppose.
And if the Tech 2 will allow me to operate devices as you describe, that's the kind of tool I'm looking for.
(For the record, I'm an industrial automation electrician. Robots and servos and equipment like that. But troubleshooting a modern vehicle without tools or drawings? Forget about it!)
Thanks for the input.

Click to expand...

This reminds me of a YouTube video from "South Main Auto" which is a channel that focuses diagnosing and repairing vehicles. He has done several videos on no crank no start GM vehicles and it turned out to be a bad/worn out ignition switch. Not the key cylinder, but the actual switch in the steering column. If you know how to check for voltage and all, I would start probing the wiring at the ignition switch and possibly rule that out, or else solve your issue. Just my 2 cents.