NEED HELP obdii problem

[05envoy]

i have been trying to get the codes read on my envoy.
using both dash command and a plug in reader
they both say there is no connection to the ecm
i found a 1k ohm resister from the lite blue wire
and the dark blue wire on the obd socket
any one have any ideas ?
i cut the resister and disconnected the joint and have not found any changes

 

[BlazingTrails]

Check the fuse for the lighter/aux plug. It is located in the fuse panel under the hood.

 

[Wooluf1952]

Fuse #13

 

[05envoy]

that's the plug i use to charge my hands free it works
there is power to the blue tooth dongle that plugs into
the obd socket
any ideas about the 1k ohm resister?

 

[Sparky]

But do both sockets work? I think they are on two different fuses IIRC.

Not sure about the resistor...

 

[Mooseman]

How long have you had the truck? Maybe something modded by the previous owner? As far as I know, there should be anything behind the OBD pplug except the wires. Maybe download the manual (link in my sig) and check the schematics.

 

[05envoy]

i have had the envoy about two months now
i know i have seen somewhere on the site a picture of
the obd socket and the voltages on the pins but i have not been able to search for it again

 

[budwich]

more than likely, its a termination resistor. It appears that GM puts them in their "buses".... having "unterminated" data lines is probably not a good idea overall.

 

[coolasice]

i have had the envoy about two months now
i know i have seen somewhere on the site a picture of
the obd socket and the voltages on the pins but i have not been able to search for it again

Here is the pinout for the DLC connector
There is supposed to be a 121Ohm resistor between both High and Low side of the GM Lan data wires.


And because I'm such a nice guy, here's the DLC Schematic:

 

[05envoy]

thank you coolasice
you wouldn't have he values on the terminals ie voltage or if they are grounds?
i know i saw it somewhere on the site
cannot find it now
thanks

 

[coolasice]

3 of them are data lines (can't measure voltage on these), battery is 12v and ground is 0.

 

[05envoy]

i thought at least one is at 5v

 

[coolasice]

The data line may read as possible 5v but is because the data is constantly changing thus tricking the DC voltmeter in thinking it is 5v DC. You would need a scope to see the actual data changes.

 

[budwich]

I guess the question is... have you ever had any "obd device" ever work?
Iirc, I think that I have seen some posts some where related to issues with 2005 "talkings" but may be mistaken (gm changed over from one protocol to another in 2005-2006). If it did work at one time and not now, you might have a bus driver problem in the pcm.... :-(
Inspect the pins in the connector to ensure that they are seated properly.
You don't have an after market radio with "adapter" installed?

 

[05envoy]

i have a gm radio
used a couple of scanners from a guy down the street same result
no connection to the ecm
he works for the city repairing trucks in there works yard
suggests it might be bad grounds or bad ecm
i did have one program work giving a random misfire code
that was using a obd dongle

 

[Mooseman]

Sounds like a bad connection at the port. Check the pins and wiring.

 

[triz]

Did you check the Cig fuse? I did not see if you did.

Long story short...many lights went off in my TB(every possible light on the dash) , OBD was not working, windows not working, cig lighter was working. Guages were working off and on, unknown driver displayed. Looked at the cigar fuse and it was blown. Replaced. Everything workie!

 

[05envoy]

i have spent many hours searching the site for repair ideas
done all the suggestions already

 

[BlazingTrails]

i have spent many hours searching the site for repair ideas
done all the suggestions already

I hope you don't take this as me being rude because it is not my intention, but everything that has been mentioned above are the only things that can cause the problem. you have power, ground, and communication wiring to check, if it is good double check the connections to the PCM, if that is good and your fuse is good you have a problem with your handheld device. this is a very simply interface. You need to get at the port with a DMM and check every wire, you may have power and have a cut ground wire? who knows?

 

[Mooseman]

What kind of code reader do you have? Maybe yours is too old or not compatible. I have an older one that won't read my GMT's but reads my son's old Honda. Probably because it's not CANBUS compatible.

 

[05envoy]

i am using a bafx bluetooth dongle and a tablet with dashcommand
plus several other obd testing programs the scanner is a autel al519
they both work on the caravan
i am thinking its more of a ground problem
weather is to rainy to work in the driveway
one of the programs did connect once to give a misc misfire code
will be checking the socket next

 

[mcsteven]

Show us the OBD-II device. I had 4 of them, all worked on some Fords, none worked on my Envoy. I spent a few extra bucks and got a better one recommended by a few people. Mounce ordered and confirmed it worked just before I ordered one. But as I went back to look at the posts to confirm the brand, it appears you have that one - the BAFX one.

http://www.ebay.com/itm/251488093341

Any chance you have access to another, preferably same year, GMT360 or 370 to check it on?

 

[05envoy]

that's the one i have i did manage to pull codes one time
next step is to check the obd socket in the truck
waiting for a nicer day

 

[djthumper]

DO you have any other vehicles to test it on to make sure it is working? As stated there have been some that have worked great on older and other vehicles.

 

[05envoy]

i used it on the carvan worked fine there
i have a nephew in law with a tahoe will give him a call to test his truck