Three Pin MBE ECU Cable How To

[aide]

Hi

I have the three pin ECU connection my car.

Which looks like this:


When I wanted to connect my laptop to the car I couldn't just buy a usb-to-rs232 cable and connect it up.

I actually needed an extra cable that had a female rs232 and a male three pin tvr ecu connector..

So I ended up making one - two actually

It was easy to put together. The hardest part was finding the three pin tvr ecu connector.
Which I did find for sale from a tvr parts shop, but they were a massive rip off for both the part and the postage imho.

So searched and found the RS Part for the Male Three Pin Connector:

And the Trident pins:


I then just got a bit of cable, some shrink-wrap, a female rs232 connector and housing from Maplin:


Soldered it together:

(Remember that GND on the rs232 pinout corresponds to the middle terminal on the three pin connector, the other two are Rx and Tx)

And ended up with this:


It's getting hard to buy this cable these days so I thought it would be a good idea to share the knowledge on how to make your own.

Best wishes
Aide

[aide]

scotty_d said:

I would have just cut the old connection off and fitted a 9 pin d sub connector. But a tidy job none the less.

That would work scotty, bit of a bodge, but could be done.
Not sure if I'm getting old, but somehow I don't fancy lying upside-down in the passenger footwell with a head torch, a soldering iron, a d-sub connector and only 5cm of cable to work with.. [oh 5h1t, where did I put the solder!]

[aide]

gruffalo said:

Aide, you don't fancy knocking a few up and flogging them do you?

Could do a batch of 10 perhaps. But it's a nice project to do at home yourself too!

[aide]

SimonKD said:

Great guide Aide

Any chance of a pin out guide saying which pins of the 9 pin RS232 connector correspond to the 3 pins of the ECU connector?

Regards

Simon

The three pin connector has GND, Tx and Rx.
Remembering that the middle of the 3 pin connector is Rx.
Off the top of my head:

3 Pin	RS232
Rx	Pin 2
GND	Pin 5
Tx	Pin 3

(I might have Rx and Tx mixed up - but as long as you have GND conneccted correctly, if you get Rx and Tx the wrong way around, it's fine, just swap them)

HTH
Aide

Edited by aide on Wednesday 22 April 20:51

[aide]

gruffalo said:

aide said:

gruffalo said:

Aide, you don't fancy knocking a few up and flogging them do you?

Could do a batch of 10 perhaps. But it's a nice project to do at home yourself too!

I just thought that if you have left over connectors and pins you may wish to put them to good use.

Ahh, I see what you mean. I think I have enough bits and bobs left to make another one.

[aide]

gruffalo said:

If that is an offer then yes please Aide.

Will have a look and see what I have when I get home from the holidays..

[aide]

But that is a serial to usb converter?
Have to admit it's pretty neat.

ETA: are you going to just add a three pin connector to the end of the new cable? That would be a really nice alternative.

Edited by aide on Wednesday 6th August 14:55

[aide]

thefrog said:

aide said:

But that is a serial to usb converter?

It is

aide said:

ETA: are you going to just add a three pin connector to the end of the new cable? That would be a really nice alternative.

Yup

Nice one! it's certainly a neater alternative and you should make 10 as there are a few people, including myself, that would like one I'd say.

The crimp tool for the trident pins is a bit expensive - if you don't already have one let me know.

[aide]

thefrog said:

I haven't placed the order yet, so if there are interested parties, I'd be willing to get a job lot and sort it out. I'll have ten of the three way connectors anyway since you can't order them in singles.

Crimping... yikes.... I thought they needed soldering... might have to rethink the above plan !

yes, the trident pins need crimping (I also soldered them once they were crimped as well)
I'll post my crimp tool to you.

ETA: A piece of software I'm working on can only sense and use the Prolific chipset based USB to Serial converters.. I'm interested in one of these cables because it uses the FTDI chipset for it's USB to serial converter.

Edited by aide on Wednesday 6th August 18:06

[aide]

1. aide

[aide]

Just checking.

I think you need this version of the cable:
USB-RS232 Converter Cables: USB-RS232-WE-1800-BT_0.0
http://www.ftdichip.com/Products/Cables/USBRS232.h...

[aide]

thefrog said:

Anyone who's interested, please add your name to the list Aide started, however we need to check this will actually work with Aide's app.

Aide, this appears to be what RS Components come up with the reference you provided above, can you check it's the same ?

http://uk.rs-online.com/web/p/kvm-mixed-cable-asse...

Yep. That's the one.

[aide]

paulh1975 said:

Hello my name is paul.. having problems.. I have a cerbera and my ecu inside the box has a 9 pin female serial cable.i have bought a usb lead from rs componts. like you all say. don't no what cables colours go to what 9pin..any one got a diagram to show how this is made please..!

Hi Paul
You don't need a bespoke cable if you have an earlier ecu.
Just a standard usb-to-rs232 cable off of Amazon or maplin should suffice.
HTH!
Aide

[aide]

The three pin connector has GND, Tx and Rx.
Remembering that the middle of the 3 pin connector is Rx.

3 Pin	RS232
Rx	Pin 2
GND	Pin 5
Tx	Pin 3

[aide]

philip600 said:

Hi, sorry if I sound a numpty but I just want to double check a few things. I've bought the cable that thefrog has in his earlier post & the 3 pin plug & pins. I've connected it up as follows -

Orange - TX - Pin 1
Yellow - RX - Pin 2
Black - GND - Pin 3

Can someone confirm this is correct ?
And also that I can then plug this into a laptop directly without the need for a serial to USB adaptor shown earlier ?

I've also downloaded the RS-AJP app onto my HTC One M8 android phone & have bought a USB 3.0 female to female convertor so I can join my phone lead to the USB lead I've made up, should this work OK ?
Many thanks, Phil.

Hi Phil

Can I suggest that it's far easier to get yourself up and running if you use the cables listed on the Play store.

Once you're connected and running the app it's much more fun working out the best way to connect/power/mount etc..

HTH
Aide

[aide]

This should help..

From another (really really long) thread:

[thanks FYP!]

FarmyardPants said:

Pic of my rs232 cable:

FarmyardPants said:

Links for making the above cable:

http://www.hobbytronics.co.uk/serial-db9-ribbon-fe...
http://www.hobbytronics.co.uk/serial-db9-ribbon-ma...
http://www.hobbytronics.co.uk/ribbon-cable-9 (Sold by the metre)

[aide]

philip600 said:

Ok, made my cable using the guide & connections as above. Then bought serial port to USB cable & USB to micro USB (OTG) cable as shown on play store site, plugged into 3 pin connector in passenger footwell & HTC One M8 android phone. Disable immobiliser & turn on ignition, RS-AJP app launches but no data showing, start engine, still no data. What am I doing wrong ? Kind Regards, Phil.

My guess would be the cable you made.
(You do know that if you take the lid off your ecu there is a 9pin connector that you can use to connect with directly?)

[aide]

aide said:

philip600 said:

Ok, made my cable using the guide & connections as above. Then bought serial port to USB cable & USB to micro USB (OTG) cable as shown on play store site, plugged into 3 pin connector in passenger footwell & HTC One M8 android phone. Disable immobiliser & turn on ignition, RS-AJP app launches but no data showing, start engine, still no data. What am I doing wrong ? Kind Regards, Phil.

My guess would be the cable you made.
(You do know that if you take the lid off your ecu there is a 9pin connector that you can use to connect with directly?)

Not sure if you're aware, but all the cables you need are freely availiable and listed!
HTH
Aide.

[aide]

philip600 said:

aide said:

philip600 said:

Ok, made my cable using the guide & connections as above. Then bought serial port to USB cable & USB to micro USB (OTG) cable as shown on play store site, plugged into 3 pin connector in passenger footwell & HTC One M8 android phone. Disable immobiliser & turn on ignition, RS-AJP app launches but no data showing, start engine, still no data. What am I doing wrong ? Kind Regards, Phil.

My guess would be the cable you made.
(You do know that if you take the lid off your ecu there is a 9pin connector that you can use to connect with directly?)

Hi, I did know I could do that but would prefer not to take ecu out if I can help it. With regards the cable, I've made it using your guide, soldered the connections & have checked them for continuity with a multi-meter so I'm confident the cable is fine & I've checked & double checked the cables are connected as shown ? All the other cables are as recommended on your page. Is there any settings on my phone I need to check ?

Hi Phil

I really, and as politely and sincerely as possible, haven't time to check everyone's attempt to make a cable. And making your own cable, although cheaper, is probably an order of magnitude riskier than either:
A) simply opening the ecu cover and plugging-in an off the shelf serial cable or
B) buying the 3pin cable to externally connect instead of making your own.

As far as I'm aware there are no settings that need to be altered in order for the app to work.

All the best
Aide

[aide]

From the PlayStore:

"(v1.07) Well, it was said that the Cerbera, from 0-100mph, will out drag a Tornado Jet.
A Tornado Jet has a Head Up Display, so I thought it fitting that a Cerbera should have one too
RS-AJP (v1.07), with HUD...Enjoy!"

You have inadvertently enabled HUD mode - it's a menu option.

So:
Menu->Options->DisableHUD

Then (to get the layout back):
Menu->Options->Reset GPS Layout

HTH!
Aide