ELM323 / ELM327 OBD-II

[22Fast4U]

שלום,

 

לצורך דיאגנוסטיקה עבור 106 1997 GTI, האם מישהו עובד עם אחד הסורקים?!

 

מה ההבדלים בין הELM323 לבין הELM327 חוץ ממספר הקודים?

 

ציטוט רלוונטי:

 

"Before you begin

At the time of writing, I'm still reading up on OBD, specially in relation to the 106. Diagnostics documentation is very sketchy and there are a lot of conflicting reports. If you're reading this ("Before you begin"), I'm still not 100% sure what signalling protocol every 106 uses...

 

Introduction:

 

This guide will show you what you need in order to do your own diagnostics. Thanks to rich106quiksilver for finding a thread originally by MoonstoneGTI that give me all the information!

 

First of all, a few terms:

 

DTC - Diagnostics Trouble Code.

OBD - On-Board Diagnostics.

ECU - Electronic/Engine Control Unit.

MIL - Malfunction Indicator Light (commonly known as the "engine management light").

PID - Parameter ID.

 

What you'll need:

 

OBD-II to USB interface.

Laptop running Windows (XP or Vista, making sure the OBD-II interface has drivers available!).

Software.

 

Background information:

 

OBD is a way of accessing a vehicles state of health. A vehicles ECU ("the brain") collects information from the various sensors on the vehicle. When something goes wrong, the ECU logs this fault permanently and will make you aware that something is wrong by turning the MIL on.

There are several OBD interface types; OBD-I, OBD-1.5 and the interface that is now the standard is OBD-II (or OBD2). There is also EOBD which is the European version of OBD-II, implemented in all 2004+ diesel vehicles and 2001+ petrol vehicles (by law).

There are several signalling protocols too. This is the critical part.

 

(Important!) Diagnostics and your 106:

 

This is the bit I'm not 100% sure on. As above, it's the signalling protocol that's the critical part.

Unfortunately I can't find any documentation to tell me what year of 106 implements one of the five (yes, five!) different protocols. If anyone knows this information or has a document, please PM me.

However, I'm fairly sure (95%) that all 2000+ 106s (3 plug ECUs only?) implement signalling protocols ISO9141/KWP2000. For this, you need to get yourself an "ELM323 interface".

You may also notice that some of the OBD software available (like easyOBDii and ScanTool.net) can perform "live sensor readings", so you can see in real-time things like O2 levels, coolant temperature, engine load, battery load etc. Unfortunately on my 106 at least, the ECU only implements 3 PIDs. None of these PIDs are very useful: RPM, OBD compliance, time since DTCs last cleared.

Having said that, I know that MoonstoneGTI got the live sensor readings to work on his GTi. So it's possible it may work for you.

 

Edit 27/08/08: I tried my ELM323 interface on a 1998 1.1 106 (single plug ECU) and the pinout on the OBD-II interface wasn't the same, so they must use a different signalling protocol. I'll try to work out the pinout and then from there I should be able to tell what signalling protocol it uses.

 

The interface:

 

Taking in to account the above, if you've got a 2000+ 106 (3 plug ECUs only?), you will need an ELM323 OBD-II interface. The ELM323 part is the model of chip inside the interface that can interpret the OBD-II signalling protocol (in this case it's ISO9141/KWP2000).

Here is my OBD-II interface that uses the ELM323 chip (it's OBD-II to USB):

 

I picked this up off of eBay (search for: elm323) for £26 delivered, from a UK supplier.

The software:

 

Luckily, there is plently of free software available! I'm using an Open Source application called ScanTool.net, which implements DTC reading, clearing DTCs and "real-time" data logging. It has 3000 DTC codes in it's database.

You can download the software from: http://www.scantool.net/

 

Step 1:

Plug the USB cable on your interface in to your laptop. Install the drivers (which will probably be on a CDROM).

Once the drivers are installed and Windows has told you the new hardware is working, open device manager either by going to "Start -> Run -> devmgmt.msc", or right click My Computer and select "Manage".

In Device Manager, expand "Ports (COM & LPT)" and you should see a "USB Serial Port". This will give you the COM port number:

Mine is COM7. Note this.

 

Step 2:

Install the ScanTool.net software and run it. Once running, it should ask you to configure it for the first time. If it doesn't, go to the "Options":

Set the measurement system to metric. Select the COM port you noted in step 1 above. Set the baud rate to 9600. Save the options. Close ScanTool.net.

 

Step 3:

Find your OBD-II connector. This will be located on the passanger side, underneath the glove box, on the left hand side.

Looking under here and below the bonnet release handle, you'll see the following:

This is your OBD-II connector.

 

Step 4:

Simply plug your OBD-II interface in to your OBD-II connector. It'll only fit one way. On my interface, there are two green lights. When the interface is connected to the OBD-II connector they change from red to green.

 

Step 6:

With the OBD-II interface connector to the OBD-II connector on your 106, your laptop turned on and the USB cable from the interface plugged in, turn the ignition by two clicks so all the lights on the dash come on:

Now run the ScanTool.net software.

If all is well, you should now be able to click on "Read Codes" and any DTCs logged will be displayed:

Take a note of the code and any text. Before clearing codes, you'll want to make a note of them! Typing the code in to Google (i.e. P0136) will normall give you several websites that will explain the meaning, cause and possible solutions.

 

Step 7:

With all the codes noted etc. you can clear the codes and turn off the MIL. By clearing the codes, you'll reset the ECU. So don't be alarmed if for ~15 minutes after doing this, it doesn't idle as it did before etc. The ECU will need to recalibrate itself.

By clicking the "Clear" button, you'll be presented with the following warning:

If you're sure, click "Yes, I am sure". The ECU will now be fully reset and all DTCs cleared.

Hopefully you'll see no DTCs:

 

Step 8:

Start your 106. Let it idle for a while (normally ~15 minutes). You can disconnect the OBD-II interface etc. now. Finally, take your 106 for a little test drive, just to make sure it's behaving itself.

Check out the errors reported in more detail and make any adjustments. If the MIL turns on again, see if the same DTCs have occured."

 

 

תודה, עידן.