OBD-II Hardware
ECUFIX.COM Sells a number of interfaces including:
- A Opto-Isolated type.
- A ready-made professional MAX232 based lead.
DIY Opto Interface
Here is our DIY Opto OBD-II ISO interface:
The interface is fully ISO compliant, interfaces with both the K and L lines, opto-isolated from the vehicle's data-stream and comes complete with status LEDs. The flow control lines are also connected which makes the interface more universal and compatible with a wider range of software.
The version 2 board has a selectable link (LK1) which can be used in two configurations:
- A Shorted- This grounds the RX circuit thus allowing the interface to receive all traffic.
- N Shorted- This puts the RX circuit under RTS control. This is the default setting of the interface.
The version 2 interface also has the facility to fit fuses on both the K and L lines.
Professional Interface
This is a VagCom 4.09 compatible interface complete, as seen in the picture.
The OBD-II connector is the thin wall type meaning that it will easily fit most VAG cars including VW, Audi, Seat, Skoda.
The interface is fully VAG and ISO compliant meaning that it can connect to most other ISO compliant cars (e.g. European Vauxhall/Opel, Lotus V8, Rover, etc).
The interface is supplied ready-made, ready to plug in and use! Please be aware that you need a spare 9-pin COM port to use this interface. The interface also has a blue LED on the OBD-II connector to show you when power is applied. Additionally, the LED flickers when data is being received or transmitted. Why pay for someone else to tell you what trouble codes your car has stored when you can do it yourself for free?
Please note that this is for the interface only; I provide no software although VAGCOM can be downloaded from www.ross-tech.com
Technical Specification:
| OBDII Plug: |
J1962 16-Pin Male (to Car) |
| Serial Port : |
DB-9 Female (to Computer or PDA) |
| Length : |
1.5 metres |
| Weight : |
Approximately 180g |
| Colour : |
Black |
Supported Software:
- Ross-Tech VAG-COM Versions: 3xx, 4xx
- VAG Diagnose (for DOS)
Supports powerful Direct Memory Access (DMA) which allows users to modify RAM/EEPROM/SEEPROM directly through the cable without ever removing the ECU's cover. - REVO Lemmiwinks ECU Tuning
- APR Immobilizer Information Reader
- Probably other VW diagnostic and tuning software!
Buy here at ECUFix!
Please Email me for details on how to order if you are unsure. orders@andywhittaker.com
FAO
I've been asked a few questions about the above interface. Here are a few answers to the most popular questions:
- What type of RS232 lead do I need?
You need a 9-pin female to 9-pin female D-Type lead wired as a straight through configuration (also called a V24 cable).
- Pin 1 to Pin 1
- Pin 2 to Pin 2
- Pin 3 to Pin 3
- Pin 4 to Pin 4
- Pin 5 to Pin 5
- Pin 6 to Pin 6
- Pin 7 to Pin 7
- Pin 8 to Pin 8
- Where can I buy a suitable RS232 cable?
You can purchase a cable from a number of sources. I use Maplin who are on the web at http://www.maplin.co.uk/ - you can order on-line with them.
The correct cables are:
Order Code
|
Description |
| ZZ62S |
F/F 9P V24 Cbl 1.5m |
| ZV83E |
F/F 9P V24 Cbl 1.2m |
|
|
- Could I directly hang the interface at the back of my Laptop?
The interface needs a Female connector which cannot physically connect to a Laptop unless a gender changer is used. I wouldn't recommend that because the ports on a Laptop PC are very fragile. - Do I buy a bare board or a ready-made one?
This decision is up to you. It's easier for me to make the boards because I make them in batches of 10. This is a convenient number as most electronic components are sold in packs of 5, 10 or 25. I then test each board.
This is the key to the problem of making a 1 off board yourself. You'll end up buying more components than you really need thus inflating the cost of a DIY build. - What does the OBD-II Connector Look Like?
The connector that's mounted in the car looks like this:
All ISO compatible cars with have pins in all of these locations with, maybe, the exception of the L Line. The L Line is used to wake up the ECU but this can be done via the main data line (K Line) on most ECUs.
CAN Protocol Pins
If pins 5, 6, 14 and 16 are populated, the vehicle supports CAN.
| Pin # |
Description |
| 5 |
Ground |
| 6 |
Data |
| 14 |
Data |
| 16 |
Power |
ISO and KWP Protocol Pins
If pins 5, 7, 16 and, optionally, 15 are populated, the vehicle supports ISO or KWP.
| Pin # |
Description |
| 5 |
Ground |
| 7 |
Data |
| 15 |
Data (this pin is optional and may not be present) |
| 16 |
Power |
VPW Protocol Pins
If pins 2, 5 and 16 are populated, the vehicle supports VPW.
| Pin # |
Description |
| 2 |
Data |
| 5 |
Ground |
| 16 |
Power |
PWM Protocol Pins
If pins 2, 5, 10 and 16 are populated, the vehicle supports PWM.
| Pin # |
Description |
| 2 |
Data |
| 5 |
Ground |
| 10 |
Data |
| 16 |
Power |
OBD-II Software
You can use the above interface with a number of software products. Here are a few examples: