GM OBD2 scanners?

City
Halifax
State
UK
#1
Before you read this just note i am based in the UK where Chevrolet dont really exist and GM purely make passenger cars and SUVs under the name of Vauxhal!!!!!

I would like to know what do you all use or recommend to read engine/transmission codes on your modern LS swaps? I have a 2000ish Vortec 4.3 V6 out of a Blazer which fires straight up thanks to a reprogrammed ECM i obtained from the States to get around that nuisance Passlock stuff.
However i am unable to connect to this ECM with my admittedly cheap scanner that i bought off Ebay a few years ago that did work fine on a few different but more modern cars..
I removed the OBD2 plug connection out of the dashboard when i chopped the Blazer up and have spliced it in to where the proper 1999 GM wiring diagrams say its to be connected on the ECM so i think the connections are correct and as its only one data wire to talk with i am guessing its must be a thing with my "high quality" scanner.
Also tried connecting to my original ECM and its exactly the same with no connection.

I have a friend who has a GMtech2 scanner but no GM programs for it just Vauxhall (passenger cars), if i obtained the correct GM codes for that do you think that would do it?.
Or to save bothering him every 5 minutes is there a scanner available in the States i can buy thats not an astronomical cost that will do the job? i dont mind buying one as its a necessary thing with a modern engines systems but any advice or someone to point me in the right direction would be great.
Or am i just doing something fundamentally wrong and cannot see what it is which is quite possible .:rotfl:.

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Randyzzz

Blown Budget
LIFETIME
CJ-8.com Member
SOA Member
City
Redmond
State
OR
#2
My cheapie scanner connects no problem.
Do you have access to someone that owns a Snap-on or other name brand scanner? They can get most any programming needed. As a last resort, there are apps and hardware that Bluetooth codes from a plug in on your ALDL connector to your smartphone.
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#3
I have an older Innova scanner that I use on Toyotas, GMs, Nissans, etc...

I have not had a problem connecting to any OBD2 compliant car.

Have you verified if the wiring for the port is connected based on looking at it from the front vs from the rear?
 
City
Halifax
State
UK
#4
My cheapie scanner connects no problem.
Do you have access to someone that owns a Snap-on or other name brand scanner? They can get most any programming needed. As a last resort, there are apps and hardware that Bluetooth codes from a plug in on your ALDL connector to your smartphone.
Actually now you mention it i do know someone with a Snap-on scanner will see if he will lend me it for a few hours.
 
City
Halifax
State
UK
#5
I have an older Innova scanner that I use on Toyotas, GMs, Nissans, etc...

I have not had a problem connecting to any OBD2 compliant car.

Have you verified if the wiring for the port is connected based on looking at it from the front vs from the rear?
Wiring is as per the GM schematics from the C4 connector off the ECM to the connector..
Pin 16 Orange +12Volt
Pin 4 Black - Ground
Pin 5 Black with white tracer - Ground
Pin 2 Purple - Data (Goes to C4 11 on the ECM)
Pin 9 Tan (should be or once was yellow) Not required for OBD2

+!2Volt and the grounds are correct when i tested them but the grounds are fed off 1 common cable maybe if i split them and ground separately?.
If not unless there are any other suggestions i think another scanner is the best thing to try and see what happens.

OBD2scribbled on.jpg
 

sdsupilot

CJ-8 Member
CJ-8.com Member
City
OKC
State
OK
#7
I use a cheapy wifi obd2 scanner for my newer stuff. It goes through a free ap. Works pretty slick. Do you have a check engine light on, or is this more for future diagnosis.
 

ag4ever

Average Nut
LIFETIME
CJ-8.com Member
City
Richmond
State
TX
#10
If you want to tune, you also have EFILive as an option.

Both do pretty much the same thing, but in slightly different ways.

I don’t think you can change the VIN in the ECM with HP, but you can with EFI. If you really want to get into tuning, I suggest getting the same system a local tuner uses so you can get help.
 
City
Halifax
State
UK
#11
Thanks all some good info there.
At present i want it purely for present and future diagnostics on both engine and the auto, check engine light goes off once started.
As for Tuning then maybe a long way in the future once its actually on the road, but thats not going to be for a long,long time yet.
 
City
Halifax
State
UK
#12
Just to follow up that the problem appears to be my cheap scanner, tried it with a different but equally low quality cheap scanner and that connected straight away!.
Thanks everyone it was a simple thing after all!.
 
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