Tech 2 Purchase

[TJ Baker]

No good. Connections still flaky. I have gotten away with it for my use as I only have older vehicles like your Envoy that only use 3 pins, Power, Ground, and class 2 serial data.

I have mapped out the wiring through the cable/adapter as a whole, and the wiring through the adapter alone. Have still to do the DLC cable itself without the adapter and will post that all up in a few just in case anyone wants to ring out their own cabling (and check my work) or maybe even be so bold as to make their own hard wired arrangement.

 

[TJ Baker]

So this is where I got to in ringing out the DLC cable, the 19 pin Burndy to 16 pin OBD2, and then the assembled deal from Tech 2 to 16 pin OBD2. Got me all bumfuzzled a few times but I believe I got it all worked out right.

And if the imagery isn't clear enough go here....

Tech2_OBD Cable

docs.google.com

 

[Geotrash]

Impressive work! Thanks for sharing.

 

[smokymtn65]

Yes thank you!

 

[George B]

I haven't had a chance to check continuity on my cables yet but I have a new OBD connector expected to be delivered today. I will be testing this all out soon.

 

[TJ Baker]

I haven't had a chance to check continuity on my cables yet but I have a new OBD connector expected to be delivered today. I will be testing this all out soon.

I find it also curious that the OBD2 connection adapter also appears to have the wrong GM part# on it, giving the number of the loopback adapter. Either that or the documentation has it wrong!

What worked for me was to use a small jumper with alligator clips which allowed me to attach to the 16 pin OBD2 adapter, then use a backprobe (or needle & another small jumper) at the 26 pin end. This allows for manhandling the Burndy conection to check for intermittency.

It would be helpful if anyone checking theirs might verify my posted results above so that any necessary corrections can be made to the document.

 

[George B]

I find it also curious that the OBD2 connection adapter also appears to have the wrong GM part# on it, giving the number of the loopback adapter. Either that or the documentation has it wrong!

What worked for me was to use a small jumper with alligator clips which allowed me to attach to the 16 pin OBD2 adapter, then use a backprobe (or needle & another small jumper) at the 26 pin end. This allows for manhandling the Burndy conection to check for intermittency.

It would be helpful if anyone checking theirs might verify my posted results above so that any necessary corrections can be made to the document.

I downloaded your .xls and intend to fill cells as I complete the testing. Not sure when I will get to doing this but it is on my list.

 

[George B]

Received my new OBD plug end. Same issue exists with the Candi connection. Need to wiggle the connector between the tool and Candi to get the Candi connected. That is likely an issue with the plug on the Candi.

 

[Sparksalot]

Received my new OBD plug end. Same issue exists with the Candi connection. Need to wiggle the connector between the tool and Candi to get the Candi connected. That is likely an issue with the plug on the Candi.

I’m almost positive we all know which connection you’re talking about, but would you mind posting a pic. Wide enough view we can see the candi module.

 

[Sparksalot]

Here’s what I go through every time.

Initially, almost always wrapped.

POST is good.

no damn candi for you.

 

[Sparksalot]

I opened candi. Nothing obvious. Front or back of PC board.

pulled and reset the cable terminals just to be sure no oxidation of the pins.

 

[George B]

I’m almost positive we all know which connection you’re talking about, but would you mind posting a pic. Wide enough view we can see the candi module.

The one I am holding.

 

[Sparksalot]

The one I am holding.

Thanks for confirming. I figured it was, but wanted to be 200% sure.

 

[George B]

Same results connecting to the Envoy as before. Probably not the OBD adaptor/connector. WTF!

 

[Fless]

Curious, and apologize if I missed it, but have you tried powering the Tech 2 from AC power while attempting communication? If so, which power plug, the one on the Tech 2 or the one at the OBD connection?

 

[Doubeleive]

Same results connecting to the Envoy as before. Probably not the OBD adaptor/connector. WTF!

these are cheap re-pops for 1/10th the price of a real tech2 they cut corners, there is a video out there of a guy that explains the soldering points on these degrade because it is cheap solder, you might try some electronic contact cleaner? not sure

 

[Rocket Man]

these are cheap re-pops for 1/10th the price of a real tech2 they cut corners, there is a video out there of a guy that explains the soldering points on these degrade because it is cheap solder, you might try some electronic contact cleaner? not sure

Whoa, didn’t know who dis, thought it was some newb with a beefy avatar. Dude do you even lift?

 

[TJ Baker]

Same results connecting to the Envoy as before. Probably not the OBD adaptor/connector. WTF!

I find your Envoy issue truely curious. In particular because I also own an 02 GMT360. Your description of what happens with the security light and unknown driver message I expect to see with a hosed serial data line. But the cluster gauges going full scale upward is bizzare. A cluster reset drives the gauges down to the max. I have never seen nor can I duplicate an upswing on my frankenstein benchtop of PCM, BCM, Cluster, Ignition switch and whatever other random modules I throw on there.

The Envoy connects with no more than 3 wires, power, ground, and serial data. If the DLC cable and obd2 adapter are sound that points to a bad VCI I would have to guess

 

[George B]

Curious, and apologize if I missed it, but have you tried powering the Tech 2 from AC power while attempting communication? If so, which power plug, the one on the Tech 2 or the one at the OBD connection?

Not using AC adapter. I was originally not using any additional power. Just the OBD port power. I have been trying out using the DC adapter attached at the OBD connector end of the cable with better results. Need to take note of what works best.

 

[George B]

I find your Envoy issue truely curious. In particular because I also own an 02 GMT360. Your description of what happens with the security light and unknown driver message I expect to see with a hosed serial data line. But the cluster gauges going full scale upward is bizzare. A cluster reset drives the gauges down to the max. I have never seen nor can I duplicate an upswing on my frankenstein benchtop of PCM, BCM, Cluster, Ignition switch and whatever other random modules I throw on there.

The Envoy connects with no more than 3 wires, power, ground, and serial data. If the DLC cable and obd2 adapter are sound that points to a bad VCI I would have to guess

I’m sorry. I described that wrong. When the issue occurs the gauges all drop to zero not full scale. The security light comes on and the dic displays UNKNOWN DRIVER. I also note several U codes for loss of communication with several modules but I haven’t written them down. It always happens when the tech2 completes boot and flashes to the start screen. I have had luck with powering the tool with the aux power connected to the cable on the OBD end and allowing it to boot then plug into the truck and turn the key on. Sorry for the confusion.