Ls1 obdii

[AC COB]

Hi Guys,

I was down at Walkinshaw Performance talking about dyno runs and tuning with them. After explaining what I had they said it would make it much easier to tune with an OBDII plug instead of having to remove the PCM everytime, I have to agree because I tucked the PCM up inside the passenger footwell.

So does anyone have a wiring diagram for an OBDII plug for an LS1 that they could email me? Also apart from a wreckers where I could get the OBDII socket.

Any help would be much appreciated.

Cheers,
Guy

[boxhead]

Hi there Guy, I do have all LS1 wiring harness diagrams on PDF, but they are at work and I wont be back till Monday.
If you have had no luck by then shoot me a PM with your email and I will email them to you.

And I can agree that having the plug in place does make life much easier, you only need 3 wires (I think) into the plug to make what you need work.
I think I still have that instructions, but if I dont then I am pretty sure Gav does.

[Modena]

the only catch is (from memory) that reading/writing through the plug is many, many times slower than connecting direct to the PCM

[Doubledip]

Originally Posted by Modena

the only catch is (from memory) that reading/writing through the plug is many, many times slower than connecting direct to the PCM

HUH??? dont think so....

12V Battery power --> ODB2 Pin 16
Earth --> ODB2 Pin 4
Earth --> ODB2 Pin 5
Pin 58 Blue Plug LS1 --> ODB2 Pin 2


who wired you harness with out a ODB2 plug? only half a job ....

[Modena]

Originally Posted by Doubledip

HUH??? dont think so....

I may very well be wrong, but in the early days of LS1 Edit I'm sure I remember this being the case? The tuners even went to the trouble of connecting to the PCM under the bonnet in that tight hot space because of this......no?

[Doubledip]

I would think that was more the problem with the software than the car....

Do think that a car manufacturer would put a plug in the car to program with but know they have to remove the pcm

The 10 years I worked at Holden and still 10 years later they still don't have any form of on bench off car programming

[Aussie Mike]

Plugging into the OBD2 port or direct to the ECU is the same. They both use the same serial data pin.

Serial data (pin 58) is a yellow wire from memory.

Cheers

[Gaz64]

Originally Posted by Modena

the only catch is (from memory) that reading/writing through the plug is many, many times slower than connecting direct to the PCM

The reason being the PCM runs at a faster speed and speaks a different language hence the need for a PIM (Powertrain Interface Module) in a VT-VZ Commodore.

[boxhead]

Gary, there is no PIM needed in the LS1 Cobra, unless your running secondary systems from Commonwhore (ABS, Dash etc)
The serial data wire goes directly from ecu to the OBDII connector (not through PIM)

[Gaz64]

Originally Posted by boxhead

Gary, there is no PIM needed in the LS1 Cobra, unless your running secondary systems from Commonwhore (ABS, Dash etc)
The serial data wire goes directly from ecu to the OBDII connector (not through PIM)

That's handy to know, thanks for the info.

Commonwhore (ha ha, I'll have to remember to use that now and then, tongue in cheek)

[Doubledip]

Originally Posted by boxhead

Gary, there is no PIM needed in the LS1 Cobra, unless your running secondary systems from Commonwhore (ABS, Dash etc)
The serial data wire goes directly from ecu to the OBDII connector (not through PIM)

even in a commodore with the PIM in place the scan/flash tool is still connected directly to the PCM and not going through the PIM so there is no speed difference whether programming on bench with PCM alone or in a car (with or without PIM and other devices)

[Gaz64]

Ah yes, the PIM interfaces to the rest of a vehicle that can't talk as fast.

[sideshow]

its not really the speed that is the problem

ls1 ecu is usa language
commodore dash is aussie language
pim is there only on v8s to convert serial data from ls1 ecu
to the language of the aussie dashes and bcms
in usa they dont normally have pims

also obd2 is just name of the plug
this was invented i think by usa decause they got sick of every car that was make or imporeted had a different plug and companies that sell scanning tools had to make new plugs to suit and shop owners got the sheits
so they said look we want to standardise the diagnostic plug

there is still 4 or 5 different lanquages in the obd2 depending on car maker

[Rob. Smith]

Originally Posted by sideshow

its not really the speed that is the problem

ls1 ecu is usa language
commodore dash is aussie language
pim is there only on v8s to convert serial data from ls1 ecu
to the language of the aussie dashes and bcms
in usa they dont normally have pims

also obd2 is just name of the plug
this was invented i think by usa decause they got sick of every car that was make or imporeted had a different plug and companies that sell scanning tools had to make new plugs to suit and shop owners got the sheits
so they said look we want to standardise the diagnostic plug

there is still 4 or 5 different lanquages in the obd2 depending on car maker

Here's a question....What's the difference between OBD1 & OBD2....just the plug ? Because I want to buy a diagnostic reader but have an OBD1 car as well as an OBD2

[boxhead]

Originally Posted by Doubledip

even in a commodore with the PIM in place the scan/flash tool is still connected directly to the PCM and not going through the PIM so there is no speed difference whether programming on bench with PCM alone or in a car (with or without PIM and other devices)

Yes, this is what I was saying, just didnt actually say it.
I kept my answer to short.

[Aussie Mike]

The OBD2 interface and command set is standard but there are 5 different protocols available I believe. Plus like any standard it's open to interpretation. My LandRover runs OBD2 as well but the scan tool for the LS1 doesn't work with it.

One of the reasons the OBD2 (On-Board Diagnostics) interface was developed was for authorities to easily check the status of the vehicle emissions controls. A tech at a testing station can easily plug in and verify the operation of the fuel and emissions systems components.

Cheers

[sambo]

Interesting thread. I've got an OBD2 port (thanks Doubledip/Sideshow) and I was wondering the other day whether there was a cheap laptop cable and software to read error codes, log data, etc. Any suggestions? Mine's a VE C'dore tune.

Eg, what does "read live PCM data stream" actually provide?

http://cars2.ebay.com.au/OBD2-EOBD-S...mZ200445531973

[sambo]

Has anyone used any of these ODB2 scan tools?

ElmScan 5 Compact Scan Tool

MaxScan GS500

OBDLink Scan Tool

[AC COB]

Thanks everyone for the info, I'm good to go now.
I didn't initially think I would need need an OBD2 plug and that all the tuning could be done on the bench. The bloke at Walkinshaw performance said you are just wasting money having to pull the PCM out every time to adjust the tune much easier to plug in while on the run.
Plenty of useful info from and for everyone, boring day if you don't learn something new.
Cheers,
Guy

[hsv300]

Anyone got an iPhone this looks ok DashCommand is the ultimate OBD-II supplementary vehicle instrumentation application. Link to Web site